Notice of General Meeting Monday, 7th April 2025 at 11.00am Venue: Lochside House 3 Lochside Way Edinburgh EH12 9DT U.K NuCana plc 77-78 Cannon Street, London, England, EC4N 6AF Company number: 03308778 1 NOTICE OF GENER

Notice of General Meeting Monday, 7th April 2025 at 11.00am Venue: Lochside House 3 Lochside Way Edinburgh EH12 9DT U.K

77-78 Cannon Street, London, England, EC4N 6AF

Company number: 03308778

NOTICE OF GENERAL MEETING

NOTICE is hereby given that a general meeting of NuCana plc (the Company ) will be held on 7 April 2025 at 11.00am at Lochside House, 3

Lochside Way, Edinburgh EH12 9DT, UK for transaction of the following business:

Ordinary Resolutions

To consider and, if thought fit, pass the following Resolutions (1 to 2 inclusive), which will be proposed as ordinary resolutions:

To consider and, if thought fit,

pass the following Resolutions (3 to 4 inclusive), which will be proposed as special resolutions:

The directors of the Company consider that all the proposals to be considered at the general meeting are in the best interests of the Company and its

shareholders as a whole and are most likely to promote the success of the Company. It is essential that the proposed resolutions are passed. Failure to do so would severly compromise the Company s ability to finance its plans on a continuing

basis. The directors unanimously recommend that you vote in favour of all the proposed resolutions as they intend to do in respect of their own beneficial holdings.

YOUR VOTE IS IMPORTANT. Members will be able to attend the general meeting in person however you are strongly encouraged to

vote on all resolutions in advance of the general meeting by appointing the Chair of the meeting as your proxy. Further details on how shareholders can appoint the Chair of the meeting as their proxy are set out in this document.

The following notes explain your general rights as a member and your right to attend and vote at the general meeting or to appoint someone else to vote on your

CREST members and, where applicable, their CREST sponsors or voting service providers should note that EUI does not make

available special procedures for any particular messages. Normal system timings and limitations will therefore apply in relation to the input of CREST proxy instructions. It is the responsibility of the CREST member concerned to take (or, if the

CREST member is a CREST personal member or sponsored member or has appointed a voting service provider, to procure that his CREST sponsor or voting service provider takes) such action as shall be necessary to ensure that a message is transmitted by

any particular time. Reference should be made to those sections of the CREST Manual concerning practical limitations of the CREST system and timings.

The Company may treat as invalid a CREST proxy instruction in the circumstances set out in Regulation 35(5)(a) of the Uncertificated Securities

EXPLANATORY NOTES TO THE RESOLUTIONS PROPOSED AT THE GENERAL MEETING

The resolutions to be proposed at the General Meeting of the Company to be held on 7 April 2025 at 11.00am BST ( the Resolutions ) are

set out in this Notice of General Meeting. Resolutions 1 and 3 relate to a proposed restructuring of the Company s share capital, and Resolutions 2 and 4 are being proposed to grant the directors authority to allot new shares in the Company on

a non-preemptive basis. The overall intention of the Resolutions is to enable the Company to effectively raise equity capital by issuing additional American Depositary Shares ( the ADSs ). The

following notes provide a more detailed explanation of the resolutions being put to shareholders.

Ordinary Resolutions

Resolutions 1 and 2 are proposed as ordinary resolutions. Assuming that a quorum is present, an ordinary resolution is passed on a show of hands if it is

approved by a simple majority (more than 50%) of the votes cast by shareholders present (in person or by proxy) at the meeting and entitled to vote. On a poll, an ordinary resolution is passed if it is approved by holders representing a simple

majority of the total voting rights of shareholders present (in person or by proxy) who (being entitled to vote) vote on the resolution.

Resolutions 3 and 4 are proposed as special resolutions. A special resolution requires the affirmative vote of not less than 75% of the

votes cast by shareholders present (in person or by proxy) at the meeting and entitled to vote. On a poll, a special resolution is passed if it is approved by holders representing at least 75% of the votes cast (in person or by proxy) at the meeting

who (being entitled to vote) vote on the resolution.

Background to Ordinary Resolution 1 and Special Resolution 3

The Company issues ordinary shares which currently have a nominal value of 0.04 each. Under U.K. company law the Company is prohibited from issuing

ordinary shares at a price which is less than this nominal value.

Each of the Company s ADSs in issue represents 25 ordinary shares of 0.04

each so this sets a minimum price of 1 at which each new ADS must be issued (ensuring that the ordinary shares representing each ADS are issued at a price at least equal to their nominal value). The Company s ADSs are currently trading

at a price beneath this minimum price which means that the Company is currently unable to issue new ordinary shares/ADSs at market value, inhibiting our ability to raise equity capital to support the execution of the Company s business and

Resolution 1, together with Resolution 3 below, is the Company s proposal to address this issue.

Ordinary Resolution 1: Capital Reorganisation by way of Sub-Division

Sub-Division of shares is a process by which a limited company having a share capital changes the structure of that

share capital by dividing the company s existing shares into a greater number of new shares of a smaller nominal value than before. On a Sub-Division, the total nominal value of the company s issued

share capital remains unchanged.

The Company currently has 151,923,897 ordinary shares of 0.04 each in issue ( the Existing Ordinary

Shares ). The Board proposes to carry out a subdivision and redesignation of the Existing Ordinary Shares by 1:100 so that each Existing Ordinary Share will be subdivided into 1 new ordinary share of 0.0004 each ( the New

Ordinary Shares ) and 99 deferred shares of 0.0004 each ( the Deferred Shares ) ( the Capital Reorganisation ). This will increase the aggregate number of shares in issue to 15,192,389,700

(consisting of 151,923,897 New Ordinary Shares and 15,040,465,803 Deferred Shares) and change the nominal value of each share to 0.0004.

The rights of the New Ordinary Shares and the Deferred Shares will be set out in the New Articles proposed to be adopted by the Company pursuant to Special

Resolution 3 (further details of which are set out below under the heading New Articles ).

Following the proposed Capital Reorganisation the

aggregate number of shares held (directly or by virtue of holding an ADS) by a shareholder in the Company will be higher, but the nominal value of each of those shares will be lower and the total nominal value of the shares held by a shareholder

will be unchanged by Resolution 1. The total nominal value of the Company s issued share capital following the passing of Resolution 1 will remain unchanged at 6,076,955.88.

It is important to note that each shareholder s proportionate holding, by number of shares, in the issued share capital of the company will be unchanged

following the passing of Resolutions 1 and 3.

The passing of Resolutions 1 and 3 will allow the Company to issue new ADSs as the minimum price of an ADS

will then become 0.01 (given that the nominal value of 25 ordinary shares of 0.0004 each in the Company will be 0.01).

Resolution 3: New Articles

It is proposed under Resolution 3 that the Company adopts new Articles of Association (in the form annexed to the Notice of

General Meeting) ( the New Articles ). This is required as a result of the proposed Capital Reorganisation. The Company needs to establish the Deferred Shares and set out the rights attaching thereto. Below is a summary of the

material differences between the existing Articles of Association of the Company ( the Current Articles ) and the proposed New Articles.

The New Ordinary Shares will have the same rights as the Existing Ordinary Shares including with respect to

voting, dividends, returns of capital and other rights.

The Deferred Shares will have no dividend or voting rights and, upon a return of capital, the

right only to receive the amount paid up thereon after the holders of the New Ordinary Shares in the capital of the Company have received the amounts entitlted to be paid to holders of New Ordinary Shares in the share capital of the Company and the

further payment of 10,000,000 in respect of each New Ordinary Share. Deferred shares are commonly used by U.K. public companies to restructure the nominal value of their ordinary share capital. Once created for this reason, it is not uncommon

for deferred shares to be cancelled using one of the procedures available to the Company under U.K. company law and the Board will in due course consider whether cancellation is necessary or desirable and update shareholders accordingly.

No share certificates will be issued in respect of the Deferred Shares and the CREST accounts of holders of New Ordinary Shares will not be credited with any

A copy of the Company s Current Articles and the proposed New Articles will be available for inspection during normal business

hours (excluding Saturdays, Sundays and bank holidays) at 3 Lochside Way, Edinburgh EH12 9DT from the date of this Notice until the close of the General Meeting. The proposed New Articles will also be available for inspection at the General Meeting

at least 30 minutes prior to the start of the meeting and up until the close of the meeting.

THE BOARD RECOMMENDS YOU VOTE FOR THE CAPITAL

REORGANISATION (RESOLUTION 1) AND FOR THE ADOPTION OF THE NEW ARTICLES (SPECIAL RESOLUTION 3).

Background to Ordinary Resolution 2 and Special

As a matter of U.K. company law, directors of a company incorporated in England must have authority from shareholders to allot or grant

rights to subscribe for, or to convert any security into, the company s shares. In addition, when an allotment of shares is for cash, the company must first offer those shares on the same terms to existing shareholders of the company on a pro-rata basis (commonly referred to as statutory pre-emption rights) unless these statutory pre-emption rights are dis-applied, by approval of the shareholders.

Resolutions 2 and 4, which we refer to as our Share Issuance

Proposals, ask our shareholders for authority for the directors to allot shares or grant rights over shares up to an aggregate nominal amount of 20,000,000 and the power for the directors to allot shares or grant rights over shares for

cash up to an aggregate nominal amount of 20,000,000 on a non-preemptive basis.

These Resolutions, if

passed, extend (and replace) the power and authorities given at the 2024 AGM, which would otherwise have lapsed at the conclusion of the 2025 AGM. Given that we will be holding our 2025 AGM in June 2025, we feel it is sensible for the authorities

contained within the Share Issuance Proposals to last for a slightly extended period, commencing now and lasting until 30 June 2026 or, if earlier, the conclusion of our 2026 AGM, rather than expiring and having to be re-taken at the imminent 2025 AGM.

Many of our peer companies are incorporated in the United States, and are thus not

subject to similar share issuance restrictions. We are asking you to approve our Share Issuance Proposals to allow us to continue to execute on our business and growth strategy in a timely and competitive manner.

Should our shareholders not approve Resolutions 2 and 4, whilst we appreciate that we would still have the ability to seek shareholder approval in connection

with a specific issuance of shares on a case-by-case basis by convening general meetings from time to time, we do not believe that such an approach is a workable

alternative to obtaining approval of Resolutions 2 and 4 at the General Meeting as we propose. The uncertainty as to whether we could obtain shareholder approval for a specific issuance, as well as the delays we would experience in seeking and

obtaining such approval, could be harmful to the terms of such a share issuance. In addition, the case-by-case approval approach ignores market windows and other deal

timing and competitive realities.

Specifically, the requirement to first offer shares, that we propose to issue for cash, to all of our existing

shareholders by way of time-consuming pro-rata rights offerings would considerably reduce the speed at which we could complete capital-raising activities undertaken in furtherance of our growth strategy. It

would also increase our costs, might otherwise make it difficult or impossible for us to complete such transactions, and could put us at a distinct competitive disadvantage relative to our peer companies.

Access to capital and the ability to raise equity capital at short notice have been important factors that have contributed to our ability to execute our

long-term growth strategy. In practice, offering shares to existing shareholders in accordance with U.K. statutory pre-emption rights can be time-consuming, so U.K. market practice for listed companies is to

annually seek a shareholder resolution waiving or dis-applying pre-emption rights over new share issuances for cash, up to an agreed limit.

We fully appreciate that our proposals are in excess of the investment advisory guidance in this regard and for this reason, our proposals may attract a

negative voting recommendation from certain proxy advisory firms. However, we have an established track record since our IPO in October 2017 of securing annual shareholder support for a resolution dis-applying

pre-emption rights over amounts of share capital in excess of the investment advisory guidance. Using these authorities, we have responsibly raised capital in order to execute our business plan.

We believe the request for authorisation and disapplication of