Exhibit 5.1




Our ref CGG/787816-000001/69236608v4



Arqit Quantum Inc.


PO Box 309, Ugland House


Grand Cayman




Cayman Islands  



18 January 2022


Arqit Quantum Inc.


We have acted as Cayman Islands counsel to Arqit Quantum Inc. (the "Company") to provide this legal opinion in connection with the Company's registration statement on Form S-8, including all amendments or supplements thereto (the "Form S-8"), filed with the United States Securities and Exchange Commission (the "Commission") under the United States Securities Act of 1933 (the "Act"), as amended (the "Registration Statement") relating to the registration of (a) 8,094,309 ordinary shares of the Company of a par value of US$0.0001 each, (the "Shares"), to be issued in connection with the granting of certain awards under the Arqit Quantum Inc. 2021 Incentive Award Plan (the "Plan"), and (b) 8,106,425 Shares issuable upon the exercise of certain previously issued options (the “Options”).


1Documents Reviewed


We have reviewed originals, copies, drafts or conformed copies of the following documents, and such other documents as we deem necessary:


1.1The certificate of incorporation dated 26 April 2021 and the amended and restated memorandum of association of the Company adopted on 2 September 2021 (the "Memorandum and Articles").


1.2The minutes (the "Minutes") of the meeting of the board of directors of the Company held on 30 August 2021 (the "Meeting") and the corporate records of the Company maintained at its registered office in the Cayman Islands.


1.3A certificate of good standing with respect to the Company issued by the Registrar of Companies (the "Certificate of Good Standing").







1.4A certificate from a director of the Company a copy of which is attached to this opinion letter (the "Director's Certificate").


1.5The Plan.


1.6The Registration Statement.




The following opinions are given only as to, and based on, circumstances and matters of fact existing and known to us on the date of this opinion letter. These opinions only relate to the laws of the Cayman Islands which are in force on the date of this opinion letter. In giving the following opinions, we have relied (without further verification) upon the completeness and accuracy of the Director's Certificate and the Certificate of Good Standing. We have also relied upon the following assumptions, which we have not independently verified:


2.1The Plan has been or will be authorised and duly executed and unconditionally delivered by or on behalf of all relevant parties in accordance with all relevant laws (other than, with respect to the Company, the laws of the Cayman Islands).


2.2The Plan is, or will be, legal, valid, binding and enforceable against all relevant parties in accordance with its terms under relevant laws (other than, with respect to the Company, the laws of the Cayman Islands).


2.3Copies of documents, conformed copies or drafts of documents provided to us are true and complete copies of, or in the final forms of, the originals.


2.4All signatures, initials and seals are genuine.


2.5The capacity, power, authority and legal right of all parties under all relevant laws and regulations (other than, with respect to the Company, the laws and regulations of the Cayman Islands) to enter into, execute, unconditionally deliver and perform their respective obligations under the Plan.


2.6There is nothing under any law (other than the laws of the Cayman Islands) which would or might affect the opinions set out below.


2.7The Company has received, or will receive, money or money's worth (the "Consideration") in consideration for the issue of the Shares, and none of the Shares have, or will be, issued for less than par value.


Save as aforesaid we have not been instructed to undertake and have not undertaken any further enquiry or due diligence in relation to the transaction the subject of this opinion.




Based upon, and subject to, the foregoing assumptions and the qualification set out below, and having regard to such legal considerations as we deem relevant, we are of the opinion that the Shares to be offered and issued by the Company pursuant to the provisions of the Plan or the exercise of the Options, have been duly authorised for issue, and when issued by the Company pursuant to the provisions of the Plan or the exercise of the Options for the consideration fixed thereto and duly registered in the Company's register of members (shareholders), will be validly issued and (assuming that all of the consideration is received by the Company) will be fully paid and non-assessable.







The opinions expressed above are subject to the following qualification:


4.1Under Cayman Islands law, the register of members (shareholders) is prima facie evidence of title to shares and this register would not record a third party interest in such shares. However, there are certain limited circumstances where an application may be made to a Cayman Islands court for a determination on whether the register of members reflects the correct legal position. Further, the Cayman Islands court has the power to order that the register of members maintained by a company should be rectified where it considers that the register of members does not reflect the correct legal position. As far as we are aware, such applications are rarely made in the Cayman Islands and for the purposes of the opinion given in paragraph 3, there are no circumstances or matters of fact known to us on the date of this opinion letter which would properly form the basis for an application for an order for rectification of the register of members of the Company, but if such an application were made in respect of the Shares, then the validity of such shares may be subject to re-examination by a Cayman Islands court.


4.2In this opinion letter, the phrase "non-assessable" means, with respect to shares in the Company, that a shareholder shall not, solely by virtue of its status as a shareholder, be liable for additional assessments or calls on the shares by the Company or its creditors (except in exceptional circumstances, such as involving fraud, the establishment of an agency relationship or an illegal or improper purpose or other circumstances in which a court may be prepared to pierce or lift the corporate veil).


We hereby consent to the filing of this opinion as an exhibit to the Registration Statement. In providing our consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Act or the Rules and Regulations of the Commission thereunder.


This opinion is addressed to you and may be relied upon by you and your counsel. This opinion is limited to the matters detailed herein and is not to be read as an opinion with respect to any other matter.


Yours faithfully




/s/ Maples and Calder (Cayman) LLP