to this Report on Form 6-K. Our actual results may differ materially from those contained in or implied by any forward-looking statements. Overview Silence Therapeutics plc ("we", "us", "our", "the Company" or "Silence")

Condensed consolidated income statement (unaudited)

Condensed consolidated statement of comprehensive income (unaudited)

Condensed consolidated balance sheet (unaudited)

Condensed consolidated statement of changes in equity (unaudited)

Condensed consolidated statement of cash flows (unaudited)

Notes to the financial statements

Three months ended March 31, 2022

Silence Therapeutics plc and its subsidiaries (together the Group') are primarily involved in the discovery, delivery and development of RNA therapeutics. Silence Therapeutics plc (the Company'), a public company limited by shares registered in England and Wales, with company number 02992058, is the Group's ultimate parent company. The Company's registered office is 27 Eastcastle Street, London, W1W 8DH and the principal place of business is 72 Hammersmith Road, London, W14 8TH.

These condensed interim financial statements were approved for issue on May 10, 2022.

These condensed interim financial statements do not comprise statutory accounts within the meaning of section 434 of the Companies Act 2006. Statutory accounts for the year ended December 31, 2021, were approved by the board of directors on March 16, 2022 and delivered to the Registrar of Companies. The report of the auditors on those accounts was unqualified and did not contain any statement under section 498 of the Companies Act 2006. It did, however, draw attention to the significant doubt in respect of the company's going concern.

The financial statements have not been reviewed or audited.

Basis of Preparation and Accounting Policies

This condensed consolidated interim financial report for the three-month reporting period ended March 31, 2022 has been prepared in accordance with International Accounting Standard 34, Interim Financial Reporting (IAS 34) as issued by the International Accounting Standards Board (IASB).

The interim report does not include all of the notes of the type normally included in an annual financial report. Accordingly, this report is to be read in conjunction with the annual report for the year ended December 31, 2021, which was prepared in accordance with IFRS (International Financial Reporting Standards) as issued by the IASB (International Accounting Standards Board).

The accounting policies adopted are consistent with those of the previous financial year and corresponding interim reporting period exception for the estimation of income tax (see note 9).

The preparation of interim financial statements requires management to make judgements, estimates and assumptions that affect the application of accounting policies and the reported amounts of assets and liabilities, income and expense. Actual results might differ from these estimates.

In preparing these condensed interim financial statements, the significant judgements made by management in applying the Group's accounting policies and the key sources of estimation uncertainty are disclosed in the Critical Accounting Policies, Judgments and Estimates' section on Page 20.

The Company has incurred recurring losses since inception, including net losses of 7.7 million for the quarter ended March 31, 2022. As of March 31, 2022, the Company had accumulated losses of 230.6 million and cash outflows from operating activities.

The Company expects to incur operating losses for the foreseeable future as it continues its research and development efforts, seeks to obtain regulatory approval of its product candidates and pursues any future product candidates the Company may develop.

To-date, the Company has funded its operations through upfront payments and milestones from collaboration agreements, equity offerings and proceeds from private placements, as well as management of expenses and other

financing options to support its continued operations. During 2021, the Company received $40.0 million ( 30.8 million) of the upfront payments in respect of the AstraZeneca collaboration, $45 million from a private placement of ADSs (approximately $42.0 million / 30.8 million, net of expenses) and a $14.4 million ( 10.9 million) upfront payment, net of taxes withheld, related to Hansoh collaboration executed on October 14, 2021. As of March 31, 2022, the Company had cash and cash equivalents of 59.3 million.

The Company has the responsibility to evaluate whether conditions and/or events raise material uncertainty about its ability to meet its future financial obligations as they become due within one year after the date that the financial statements are issued. The forecast for evaluating the going concern basis of the Company includes continued investment in our technology platform and product pipeline. The forecast does not include collaboration milestones which have not been fully achieved or other assumptions for potential future non-dilutive or dilutive funding sources. Based on this evaluation, the Company believes that its current cash and cash equivalents are only sufficient to fund its operating expenses for the next twelve months. This represents a material uncertainty which may cast significant doubt on the Company's ability to continue as a going concern. These consolidated financial statements have been prepared assuming that the Company will continue as a going concern which contemplates the continuity of operations, realization of assets and the satisfaction of liabilities in the ordinary course of business and does not include adjustments that would result if the Company were unable to continue as a going concern.

The Company will need to raise additional funding to fund its operation expenses and capital expenditure requirements in relation to its clinical development activities. The Company may seek additional funding through public or private financings, debt financing or collaboration agreements. Specifically, the Company may receive future milestone payments of up to $15 million from existing collaboration agreements in the next 15 months which will extend the ability to fund operations beyond the next twelve months. However, these payments are dependent on achievement of certain development or regulatory objectives that may not occur. The Company has an authorized open market sale agreement and can potentially raise funds through the sale of ADSs for an aggregate offering price of up to $100 million from time to time. The inability to obtain future funding could impact the Company's financial condition and ability to pursue its business strategies, including being required to delay, reduce or eliminate some of its research and development programs, or be unable to continue operations and ability to continue as a going concern.

Revenue from collaboration agreements for the three months ended March 31, 2022 relates to the research collaboration agreements the Group entered into with Mallinckrodt plc in July 2019 and AstraZeneca plc in March 2020.

Revenue for the three months ended March 31, 2022 comprised 5.6 million of research collaboration income (three months to March 31, 2021: 3.1 million) and 0.1 million of royalty income (three months to March 31, 2021: 0.1 million).

Under our collaboration agreement with Mallinckrodt, we received an upfront cash payment of 16.4 million ($20 million) in 2019 and are eligible to receive specified development, regulatory and commercial milestone payments. During the three months ended March 31, 2022 we received milestone payments totalling 2.2 million or $3 million (three months ended March 31, 2021: 1.5m). In addition to these payments, Mallinckrodt has agreed to fund some of our research personnel and preclinical development costs. We recognize the upfront payment, milestone payments,

payments for personnel costs and other research funding payments over time, in accordance with IFRS 15 para 35 c). During the three months ended March 31, 2022, we recognized a total of 4.9 million in revenue under this agreement.

Under our collaboration agreement with AstraZeneca, we received an upfront cash payment of 17.1 million ($20 million) in 2020 with a further amount of 30.8 million ($40 million) received in May 2021. We are also eligible to receive specified development and commercial milestone payments as well as tiered royalties on net sales, if any. We recognize the upfront payment and milestone payments over time, in accordance with IFRS 15 para 35 c). During the three months ended March 31, 2022, we recognized a total of 0.7 million in revenue under this agreement.

We entered into a collaboration agreement with Hansoh on October 15, 2021. We received a approximately 10.7 million ($16 million) upfront payment to us in December 2021. We are eligible to receive development, regulatory and commercial milestones as well as royalties on Hansoh net product sales. We recognize the upfront payment and milestone payments over time, in accordance with IFRS 15 para 35 c). There have been minimal activities performed in respect of this agreement to date.

In December 2018, we entered into a settlement and license agreement with Alnylam Pharmaceuticals Inc., or Alnylam, pursuant to which we settled outstanding patent litigation with Alnylam related to its RNAi product ONPATTRO. As part of the settlement, we license specified patents to Alnylam, and Alnylam pays us a tiered royalty of up to one percent of net sales of ONPATTRO in the European Union. We are eligible to receive these royalties until 2023. We invoice Alnylam quarterly in arrears based on sales data for that quarter as reported to us by Alnylam. Royalty revenue is recognized based on the level of sales when the related sales occur. During the three months ended March 31, 2022, we recognized a total of 0.1 million in royalty income from Alnylam.

4. Segment reporting

In 2022, the Group operated in the specific technology field of RNA therapeutics.

The Group has identified the Chief Executive Officer as the CODM. For the three months ended March 31, 2022 and 2021, the CODM determined that the Group had one business segment, the development of RNAi-based medicines. This is consistent with reporting to senior management. The information used internally by the CODM is the same as that disclosed in the financial statements.

An analysis of the group's assets and revenues by location is shown below:

5. Loss per ordinary equity share (basic and diluted)

The calculation of the loss per share is based on the loss for the three months to March 31, 2022 after taxation of 7.7 million (three months ended March 31, 2021: loss of 8.4 million) and on the weighted average ordinary shares in issue during the three months ended March 31, 2022 of 89,789,214 (three months ended March 31, 2021: 86,557,922).

The options outstanding at March 31, 2022 and March 31, 2021 are considered to be anti-dilutive as the Group is loss-making.

7. Derivative financial instruments

Derivative financial instruments related to an open forward currency contract measured at fair value through the income statement. The fair value was calculated from data sourced from an independent financial market data provider using mid-market-end-of-day data as of December 31, 2020. The derivative contract that was in place at December 31, 2020 was closed out on May 28, 2021.

The fair value of the derivative is calculated based on level 2 inputs under IFRS 13.

The fair value of financial instruments that are not traded in active market, in the case of an over-the-counter derivative, is determined using valuation techniques which maximize the use of observable market data and rely as little as possible on entity specific estimates. As all significant inputs required to fair value an instrument are observable, this derivative financial instrument is included in level 2.

The specific valuation technique used to value this derivative is the present value of future cash flow based on the forward exchange rate relative to its value based on the year-end exchange rate.

The derivative fair value movement is disclosed in the Income Statement under "Other (losses)/gains - net". For the three-month period to March 30, 2021 the gain on the derivative financial instrument was 0.3 million.

8. Contract liabilities

Contract liabilities comprise entirely deferred revenue in respect of the Mallinckrodt, AstraZeneca plc, and Hansoh Research collaborations. The current contract liabilities represent the amount of estimated revenue to be reported in

the next 12 months related to amounts invoiced to our partners. The current and non-current contract liabilities include only recharge expenses and milestones achieved through March 31, 2022.

A 1.9 million current tax asset was recognized in respect of research and development tax credits in the three months ended March 31, 2022 (three months ended March 31, 2021: 1.2 million). The asset at March 31, 2022 comprised 1.9 million in respect of research and development activity for the three months ended March 31, 2022 and 6.9 million in respect of the year ended December 31, 2021.

10. Capital reserves

The Group has only one class of share. All ordinary shares have equal voting rights and rank pari passu for the distribution of dividends.

On February 5, 2021 the Group announced a private placement of 2,022,218 of the Company's American Depositary Shares ("ADSs"), each representing three ordinary shares, at a price of US $22.50 per ADS, with new and existing institutional and accredited investors (the "Private Placement"). The aggregate gross proceeds of the Private Placement was US $45 million (approximately 33 million) before deducting approximately 2.4 million in placement agent fees and other expenses. The financing syndicate included Adage Capital Management LP, BVF Partners L.P., Consonance Capital, Great Point Partners, LLC, and other investors.

On October 15, 2021, the Company filed a registration statement on Form F-3 with the SEC to cover the offering, issuance and sale of securities from time to time in one or more offerings. The aggregate initial offering price is not to exceed $300,000,000, which includes a sale of up to a maximum aggregate offering price of $100,000,000 of ADSs that may be issued and sold under an Open Market Sale Agreement, dated October 15, 2021 with Jefferies LLC.

On November 29, 2021, the Company completed delisting from AIM. As a result, the Company converted the existing employee share options to ADSs which represents three ordinary shares and the exercise price was also converted to represent an ADS price at an exchange rate equal to the average of the last five business trading days currency conversion of sterling pounds to US dollars, which was 1.334058 sterling pounds to 1 US Dollar. This is not a modification of the existing share option grants, as the value or timing of the grants was unchanged.

Details of the shares issued by the Company during the three months ended March 31, 2022 are as follows:

11. Related party transactions

Since January 1, 2022, we have engaged in the following transactions with our directors, executive officers or holders of more than 10% of our outstanding share capital and their affiliates, which we refer to as our related parties.

In 2022, we agreed to pay Gladstone Consultancy Partnership, a company controlled by our Non-Executive Chairman, 7,500 (plus any applicable value-added tax) per month from February 1, 2022 until September 30, 2022 for consulting and advisory services to be provided by Iain Ross. Key management are considered to be Directors of the Group.

MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

You should read the following discussion and analysis of financial condition and operating results together with our unaudited financial statements as of and for the three months ended March 31, 2022 and the related notes to those financial statements included as Exhibit 99.1 to this Report on Form 6-K.

The statements in this discussion with respect to our plans and strategy for our business, including expectations regarding our future liquidity and capital resources and other non-historical statements, are forward-looking statements. These forward-looking statements are subject to numerous risks and uncertainties, including the risks and uncertainties described in Exhibit 99.1 to this Report on Form 6-K. Our actual results may differ materially from those contained in or implied by any forward-looking statements.

Silence Therapeutics plc ("we", "us", "our", "the Company" or "Silence") is a biotechnology company focused on discovering and developing novel molecules incorporating short interfering ribonucleic acid, or siRNA, to inhibit the expression of specific target genes thought to play a role in the pathology of diseases with significant unmet medical need. Our siRNA molecules are designed to harness the body's natural mechanism of RNA interference, or RNAi, by specifically binding to and degrading messenger RNA, or mRNA, molecules that encode specific targeted disease-associated proteins in a cell. By degrading the message that encodes the disease-associated protein, the production of that protein is reduced, and its level of activity is lowered. In the field of RNAi therapeutics, this reduction of disease-associated protein production and activity is referred to as "gene silencing." Our proprietary mRNAi GOLD (GalNAc Oligonucleotide Discovery) platform is a platform of precision engineered medicines designed to accurately target and silence' specific disease-associated genes in the liver, which represents a substantial opportunity. Using our mRNAi GOLD platform, we have generated siRNA product candidates both for our internal development pipeline as well as for out-licensed programs with third-party collaborators. Our wholly owned pipeline is currently focused in three therapeutic areas of high unmet need: hematology, cardiovascular disease, and rare diseases.

Our wholly owned clinical development programs include SLN360 designed to address the high and prevalent unmet need in reducing cardiovascular risk in people born with high lipoprotein(a), or Lp(a), levels and SLN124 designed to address rare hematological conditions, including thalassemia, MDS and PV. In February 2022, we reported positive topline data from the SLN360 phase 1 single-ascending dose study in 32 healthy adults with high Lp(a). In topline results from the study, SLN360 was not observed to exhibit any clinically important safety concerns, was well tolerated, and was observed to significantly lower Lp(a) in a dose dependent manner up to 98% with reductions of up to 81% persisting at 150 days. We presented detailed results from the study in a late-breaking clinical abstract at the American College of Cardiology (ACC) and the results were simultaneously published in the Journal of the American Medical Association (JAMA) on April 3, 2022. In January 2022, we started the multiple-ascending dose portion of the SLN360 phase 1 study in patients with high Lp(a) that have a confirmed history of stable atherosclerotic cardiovascular disease (ASCVD). We plan to start a phase 2 ASCVD study in the second half of 2022, pending regulatory discussions. In May 2021, we reported positive data from the SLN124 phase 1 study in 24 healthy volunteers, which was the first clinical data from our mRNAi GOLD platform. Data from the study showed that SLN124 was effective in reducing plasma iron levels, had a strong safety profile and long duration of action. In April 2021, we started evaluating SLN124 in a phase 1b program which includes two study arms, an arm in patients with non-transfusion dependent thalassemia and an arm in very-low and low-risk MDS. In March 2022, we completed enrollment in the thalassemia single-ascending dose study, which includes 24 patients, and we expect topline data from this study in the third quarter of 2022. In March 2022, we discontinued further enrollment in the MDS arm of the SLN124 phase 1 program due to recruitment challenges in this population and the decision to prioritize spend in thalassemia and PV indications where we believe we can derive the most value near term. The FDA granted SLN124 orphan drug designation for PV in February 2022, and we plan to start a phase 1b study in this indication in the second half of 2022.

The potential of our mRNAi GOLD platform has been validated through ongoing research and development collaborations with leading pharmaceutical companies, such as AstraZeneca PLC, or AstraZeneca, Mallinckrodt plc, or Mallinckrodt and Hansoh Pharmaceutical Group Company Limited or Hansoh. These collaborations collectively represent up to 16 pipeline programs and approximately $7.5 billion in potential milestones plus royalties.

There are approximately 14,000 liver-expressed genes and only around one percent of them have been targeted by publicly known siRNAs. We aim to maximize the substantial opportunity of our mRNAi GOLD platform through a combination of

building and advancing our proprietary and partnered pipelines. Through this hybrid model, we plan to significantly expand our portfolio of mRNAi GOLD platform programs by delivering 2-3 initial new drug applications per year from 2023.

First Quarter 2022 and Recent Corporate Highlights

Proprietary Pipeline

Post Period Highlights

Anticipated Milestones

Collaboration Agreement with AstraZeneca

In March 2020, we entered into a collaboration agreement with AstraZeneca to discover, develop and commercialize siRNA therapeutics for the treatment of cardiovascular, renal, metabolic and respiratory diseases. Under this agreement,

AstraZeneca made an upfront cash payment to us of 17.1 million in May 2020 (equivalent to $20.0 million as of the payment date) with a further 30.8 million ($40.0 million) received in May 2021. In March 2020, an affiliate of AstraZeneca also subscribed for 4,276,580 new ordinary shares for an aggregate subscription price of $20.0 million.

We anticipate initiating work on five targets within the first three years of the collaboration, with AstraZeneca having the option to extend the collaboration to an additional five targets. AstraZeneca has agreed to pay us $10.0 million upon the exercise of each option to collaborate on an additional target. For each target selected, we will be eligible to receive up to $140.0 million in potential milestone payments upon the achievement of milestones relating to the initiation of specified clinical trials, the acceptance of specified regulatory filings and the first commercial sale in specified jurisdictions. For each target selected, we will also be eligible to receive up to $250.0 million in potential commercial milestone payments, upon the achievement of specified annual net sales levels, as well as tiered royalties as a percentage of net sales ranging from the high single digits to the low double digits.

We continue to advance the research and development workplans for each identified target as scheduled and agreed to with our collaboration partner.

Collaboration Agreement with Mallinckrodt

In July 2019, we entered into a collaboration agreement with Mallinckrodt Pharma IP Trading DAC, a wholly owned subsidiary of Mallinckrodt plc, to develop and commercialize RNAi drug targets designed to silence the complement cascade in complement-mediated disorders. Under the agreement, we granted Mallinckrodt an exclusive worldwide license to our C3 targeting program, SLN501, with options to license two additional complement-mediated disease targets from us. Mallinckrodt exercised options to license two additional complement targets from us in July 2020.

While we are responsible for the Phase 1 clinical trial in each case, Mallinckrodt will be funding all of our research personnel costs on a full-time equivalent, or FTE, basis associated with preparing for and conducting the Phase 1 clinical trials. We are also responsible for the provision of drug product for preclinical activities and for the Phase 1 clinical trials, but any manufacturing expense relating to the Phase 1 trial will be paid for by Mallinckrodt. After completion of the Phase 1 clinical trials, Mallinckrodt will assume clinical development and responsibility for potential global commercialization.

The collaboration provides for potential additional development and regulatory milestone payments in aggregate of up to $100 million for the initial C3 target and up to $140 million for each of the two optioned complement-mediated disease targets, with such milestones relating to the initiation of specified clinical trials in specified jurisdictions, and upon the receipt of regulatory approvals by specified authorities, in each case for multiple indications. We are also eligible to receive potential commercial milestone payments of up to $562.5 million upon the achievement of specified levels of annual net sales of licensed products for each program. We are also eligible to receive tiered, low double-digit to high-teen percentage royalties on net sales for licensed products for each program. We received a research milestone payment of $2 million in October 2019 upon the initiation of work for the first complement C3 target. In September 2020, we received another $2 million research milestone payment following the initiation of work on a second complement target. In February 2021, we initiated work on the third complement target which triggered another $2 million research milestone payment. In April 2021, we received a $2.0 million research milestone for the initiation of the toxicology study for the SLN501 C3 targeting program. We achieved another $3.0 million research milestone following the submission of the SLN501 clinical trial application in March 2022.

In connection with the execution of this agreement, Mallinckrodt made an upfront cash payment in 2019 of $20.0 million (equivalent to 16.4 million as of the payment date). Under a separate subscription agreement, Cache Holdings Limited, a wholly owned subsidiary of Mallinckrodt plc, concurrently subscribed for 5,062,167 new ordinary shares for an aggregate subscription price of $5.0 million (equivalent to 4.0 million as of the payment date).

We continue to advance the research and development workplans for each identified target as scheduled and agreed to with our collaboration partner.

Collaboration Agreement with Hansoh

On October 15, 2021, we announced a collaboration agreement with Hansoh, one of the leading biopharmaceutical companies in China, to develop siRNAs for three undisclosed targets leveraging our proprietary mRNAi GOLD platform. Under the terms of the agreement, Hansoh has the exclusive option to license rights to the first two targets in Greater China, Hong Kong, Macau and Taiwan following the completion of phase 1 studies. We retain exclusive rights for those two targets

in all other territories. We are responsible for all activities up to option exercise and retain responsibility for development outside the China region post phase 1 studies. Hansoh has the exclusive option to license global rights to a third target at the point of IND filing. Hansoh is responsible for all development activities post option exercise for the third target. Hansoh made a $16 million upfront payment to us in December 2021. We achieved an undisclosed preclinical milestone in April 2022 which triggered our first $2.0 million milestone payment from Hansoh. We are eligible to receive up to $1.3 billion in additional development, regulatory and commercial milestones. We are also eligible to receive royalties tiered from low double-digit to mid-teens on Hansoh net product sales.

Financial Operations Overview

We do not have any approved products. Accordingly, we have not generated any revenue from product sales, and we do not expect to generate any revenue from the sale of any products unless and until we obtain regulatory approvals for, and commercialize any of, our product candidates. In the future, we will seek to generate revenue primarily from product sales and, potentially, regional or global strategic collaborations with third parties.

Under our collaboration agreement with Mallinckrodt, we received an upfront cash payment of 16.4 million ($20 million) in 2019 and are eligible to receive specified development, regulatory and commercial milestone payments. During the three months ended March 31, 2022 we achieved a milestone totalling 2.2 million or $3 million (three months ended March 31, 2021: 1.5m). In addition to these payments, Mallinckrodt has agreed to fund some of our research personnel and preclinical development costs. We recognize the upfront payment, milestone payments, payments for personnel costs and other research funding payments over time, in accordance with IFRS 15 para 35 c). During the three months ended March 31, 2022, we recognized a total of 4.9 million in revenue under this agreement.

Under our collaboration agreement with AstraZeneca, we received an upfront cash payment of 17.1 million ($20 million) in 2020 with a further amount of 30.8 million ($40 million) received in May 2021. We are also eligible to receive specified development and commercial milestone payments as well as tiered royalties on net sales, if any. We recognize the upfront payment and milestone payments over time, in accordance with IFRS 15 para 35 c). During the three months ended March 31, 2022, we recognized a total of 0.7 million in revenue under this agreement.

We entered into a collaboration agreement with Hansoh on October 15, 2021. We received a $16 million (equivalent to approximately 10.7 million, net of taxes based on the exchange rate at the payment date) upfront payment to us in December 2021. We are eligible to receive up to $1.3 billion in additional development, regulatory and commercial milestones. We will also receive royalties tiered from low double-digit to mid-teens on Hansoh net product sales. We recognize the upfront payment and milestone payments over time, in accordance with IFRS 15 para 35 c). There have been minimal activities performed in respect of this agreement to date.

In December 2018, we entered into a settlement and license agreement with Alnylam Pharmaceuticals Inc., or Alnylam, pursuant to which we settled outstanding patent litigation with Alnylam related to its RNAi product ONPATTRO. As part of the settlement, we license specified patents to Alnylam, and Alnylam pays us a tiered royalty of up to one percent of net sales of ONPATTRO in the European Union. We are eligible to receive these royalties until 2023. We invoice Alnylam quarterly in arrears based on sales data for that quarter as reported to us by Alnylam. Royalty revenue is recognized based on the level of sales when the related sales occur. During the three months ended March 31, 2021, we recognized a total of 0.1 million in royalty income from Alnylam.