POWER OF ATTORNEY (PUBLIC): POWER OF ATTORNEY

POWER OF ATTORNEY

The undersigned does hereby constitute and appoint Patrick Willcocks and
Noleen McDonnell as the undersigned?s true and lawful attorneys-in-fact to, as
applicable: (1) execute for and on behalf of the undersigned, in the
undersigned?s capacity as an officer or director of Arqit Quantum Inc. (the
?Company?), and submit to the U.S. Securities and Exchange Commission (?SEC?) a
Form ID, including amendments thereto, and any other documents necessary or
appropriate to obtain codes and passwords enabling the undersigned to make
electronic filings with the SEC of reports required by Section 16(a) of the
Securities Exchange Act of 1934 (the ?Exchange Act?) and the rules thereunder
and any amendments to the foregoing; (2) execute for and on behalf of the
undersigned, in the undersigned?s capacity as an officer or director of the
Company, Forms 3, 4 and 5 in accordance with Section 16(a) of the Exchange Act
and the rules thereunder and any amendments to the foregoing; (3) do and
perform any and all acts for and on behalf of the undersigned which may be
necessary or desirable to complete and execute any such Forms 3, 4 or 5,
complete and execute any amendment or amendments thereto, and timely file such
form with the SEC and any stock exchange or similar authority; and (4) take any
other action of any type whatsoever in connection with the foregoing which, in
the opinion of such attorney-in-fact, may be of benefit to, in the best
interest of, or legally required by, the undersigned, it being understood that
the documents executed by such attorney-in-fact on behalf of the undersigned
pursuant to this Power of Attorney shall be in such form and shall contain such
terms and conditions as such attorney-in-fact may approve to such
attorney-in-fact?s discretion. The undersigned hereby grants to each such
attorney-in-fact full power and authority to do and perform any and every act
and thing whatsoever requisite, necessary, or proper to be done in the exercise
of any of the rights and powers herein granted, as fully to all intents and
purposes as the undersigned might or could do if personally present, with full
power of substitution or revocation, hereby ratifying and confirming all that
such attorney-in-fact, or such attorney-in-fact?s substitute or substitutes,
shall lawfully do or cause to be done by virtue of this Power of Attorney and
the rights and powers herein granted. The undersigned acknowledges that the
foregoing attorneys-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming, nor is the Company assuming, any of the
undersigned?s responsibilities to comply with Section 16 of the Exchange Act.
This Power of Attorney shall remain in full force and effect until (1) the
undersigned is no longer required to file Forms 3, 4 and 5, as applicable, with
respect to the undersigned?s holdings of and transactions in securities issued
by the Company, or (2) any attorney-in-fact is no longer employed by the
Company or its subsidiaries, in which case this Power of Attorney will be
revoked solely with respect to such attorney-in-fact, and will otherwise remain
in full force and effect, unless earlier revoked by the undersigned in a signed
writing delivered to the foregoing attorneys-in-fact. IN WITNESS WHEREOF, the
undersigned has caused this Power of Attorney to be executed as of the 11th day
of March, 2026. By: /s/ Manfredi d?Ovidio Lefebvre Manfredi d?Ovidio Lefebvre