UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of ~~December~~April ~~2024~~2025

Commission File Number: 001-40777

ARQIT QUANTUM INC.

(Exact name of registrant as specified in its charter)

1st Floor, 3 Orchard Place

London, SW1H 0BF, United Kingdom

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F x Form 40-F ¨

EXPLANATORY NOTE

~~Extraordinary~~On ~~General~~April 4, ~~Meeting~~2025 Arqit Quantum Inc. (the “Company”) issued a press release entitled “Arqit Quantum Inc. Announces Select Preliminary Financial Results for First Half of Fiscal Year 2025,” in which the Company reported select unaudited preliminary financial results for the six months ended March 31, 2025. A copy of that press release is furnished as Exhibit 99.1 hereto.

OnThe information ~~December 18,~~furnished ~~2024,~~in ~~Arqit~~this ~~Quantum~~Report ~~Inc. (~~of Foreign Private Issuer on Form 6-K, including the ~~“Company”)~~information ~~held~~contained anin ~~extraordinary~~Exhibit 99.1, shall ~~general~~not ~~meeting~~be ofdeemed ~~shareholders~~to ~~(the~~be “~~EGM~~filed”). Atfor the ~~EGM,~~purposes ~~the~~of ~~holders~~Section 18 of 7 the Exchange Act,~~332,205~~ ~~ordinary~~or ~~shares~~otherwise assubject ofto the ~~October 29~~liabilities of that section, ~~2024~~and ~~record~~shall ~~date~~not ~~were~~be ~~represented~~deemed into ~~person~~be orincorporated by ~~proxy,~~reference ~~constituting~~into aany ~~quorum.~~filing ~~The proposal~~under ~~brought~~the ~~before~~Securities ~~the~~Act ~~EGM~~of ~~was~~1933, ~~approved~~as byamended, or the ~~Company’s~~Exchange ~~shareholders.~~Act, ~~The~~except ~~proposal~~as ~~voted~~shall onbe ~~and~~expressly ~~the~~set ~~final~~forth ~~voting~~by ~~results~~a ~~are set~~specific ~~forth~~reference ~~below~~in such filing.

The shareholders voted on a proposal to approve by ordinary resolution that the authorized share capital of the Company be increased from US$50,000.00 divided into 18,760,000 ordinary shares of a par value of US$0.0025 each and 1,240,000 preference shares of a par value of US$0.0025 each to $100,000.00 divided into 37,520,000 ordinary shares of par value of USD$0.0025 each and 2,480,000 preference shares of par value of USD$0.0025 by the creation of 18,760,000 new ordinary shares of par value US$0.0025 each and 1,240,000 new preference shares of par value US$0.0025 each in accordance with ArticleEXHIBIT ~~17.1(a) of the Articles of Association of the Company.~~INDEX

For	Against	Abstain
Exhibit No.	Description
7,287,595	40,179	4,431
99.1	Press release of Arqit Quantum Inc., dated April 4, 2025.

Other than as indicated below, the information in this Report of Foreign Private Issuer on Form 6-K shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act. The information furnished in this Report of Foreign Private Issuer on Form 6-K is hereby incorporated by reference into the Company’s registration statements on Form S-8 (File Nos. 333-262215 and 333-275960) and Form F-3 (File Nos. 333-268786 and File No. 333-259982), and shall be a part thereof, to the extent not superseded by documents or reports subsequently filed or furnished.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

ARQIT QUANTUM INC. By: /s/ ~~Nick~~Andrew ~~Pointon~~Leaver Name: ~~Nick~~Andrew ~~Pointon~~Leaver Title: Chief ~~Financial~~Executive Officer

Date: ~~December~~April 194, ~~2024~~2025

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