which is a direct wholly controlled subsidiary of Syncona Limited, a registered, closed-ended investment company, incorporated as a limited company in Guernsey, with ordinary shares publicly listed on the London Stock Exchange (LON: SYNC). 
        
        
          We or our nominees are the holder of record of Shares held for your account. A tender of such Shares can be made only by us as the holder of record and pursuant to your instructions. The Letter of Transmittal accompanying this letter is furnished to you for your information only and cannot be used by you to tender Shares held by us for your account. 
        
        
          We request instructions as to whether you wish us to tender any or all of the Shares held by us for your account, upon the terms and subject to the conditions set forth in the enclosed Offer to Purchase and the Letter of Transmittal. 
        
        
          Please note carefully the following: 
        
        
          1.
          
        
        
          The offer price for the Offer is $0.34 per Share in cash, without interest and subject to any withholding of taxes, plus one non-transferable contractual CVR per Share, which represents the right to receive one or more payments in cash, currently estimated to be up to approximately $0.73 per CVR in the aggregate (without interest and less any applicable withholding taxes), based on currently outstanding Shares and Company restricted stock units and contingent upon the achievement of certain specified milestones, upon the terms and subject to the conditions of the Offer. 
        
        
        
          2.
          
        
        
          The Offer is being made for all outstanding Shares. 
        
        
        
          3.
          
        
        
          The Offer is being made in connection with the Agreement and Plan of Merger, dated as of October 23, 2022 (together with any amendments or supplements thereto, the “Merger Agreement”), among the Company, Parent and Purchaser, pursuant to which, after the completion of the Offer and the satisfaction or waiver of certain conditions, Purchaser will be merged with and into the Company, without a meeting of the Company’s stockholders in accordance with Section 251(h) of the General Corporation Law of the State of Delaware (the “DGCL”), and the Company will be the surviving corporation and a direct wholly owned subsidiary of Parent (such merger, the “Merger”). At the Effective Time, all then outstanding Shares (other than: (i) Shares held by the Company (or held in the treasury of the Company); (ii) Shares held by Parent, Purchaser or any other wholly owned subsidiary of Parent; and (iii) Shares held by stockholders who have properly exercised and perfected their demands for appraisal of such Shares in accordance with the DGCL and have neither withdrawn nor lost such rights prior to the Effective Time) will be converted into the right to receive consideration equal to the Offer Price, without interest and subject to any withholding of taxes, upon the terms and subject to the conditions set forth in the Offer to Purchase. 
        
        
        
          4.
          
        
        
          The Offer and withdrawal rights will expire at 5:00 p.m., Eastern Time, on November 28, 2022, unless the Offer is extended by Purchaser or earlier terminated. 
        
        
        
          5.
          
        
        
          The Offer is not subject to any financing condition. The Offer is subject to the conditions described in Section 13 of the Offer to Purchase. 
        
        
        
          6.
          
        
        
          Tendering stockholders who are record owners of their Shares and who tender directly to Computershare Trust Company, N.A., the depositary and paying agent for the Offer, will not be obligated to pay brokerage fees, commissions or similar expenses or, except as otherwise provided in Instruction 6 of the Letter of Transmittal, stock transfer taxes with respect to the purchase of Shares by Purchaser pursuant to the Offer. 
        
        
        
          If you wish to have us tender any or all of your Shares, then please instruct us by completing, executing, detaching and returning to us the Instruction Form on the detachable part hereof. An envelope to return your instructions to us is enclosed. If you authorize tender of your Shares, then all such Shares will be tendered unless otherwise specified on the Instruction Form. 
        
        
          Your prompt action is requested. Your Instruction Form should be forwarded to us in ample time to permit us to submit the tender on your behalf before the Expiration Time.