<?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
  <headerData>
    <submissionType>144</submissionType>
    <filerInfo>
      <filer>
        <filerCredentials>
          <cik>0001967068</cik>
          <ccc>XXXXXXXX</ccc>
        </filerCredentials>
      </filer>
      <liveTestFlag>LIVE</liveTestFlag>



    </filerInfo>
  </headerData>
  <formData>
    <issuerInfo>
      <issuerCik>0001859690</issuerCik>
      <issuerName>Arqit Quantum Inc.</issuerName>
      <secFileNumber>001-40777</secFileNumber>
      <issuerAddress>
        <com:street1>3 ORCHARD PLACE</com:street1>
        <com:city>LONDON</com:city>
        <com:stateOrCountry>X0</com:stateOrCountry>
        <com:zipCode>SW1H 0BF</com:zipCode>
      </issuerAddress>
      <issuerContactPhone>44 203 91 70155</issuerContactPhone>
      <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Feenan Paul</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
      <relationshipsToIssuer>
        <relationshipToIssuer>Officer</relationshipToIssuer>
      </relationshipsToIssuer>
    </issuerInfo>
    <securitiesInformation>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>Fidelity Brokerage Services LLC</name>
        <address>
          <com:street1>900 Salem Street</com:street1>
          <com:city>Smithfield</com:city>
          <com:stateOrCountry>RI</com:stateOrCountry>
          <com:zipCode>02917</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>363</noOfUnitsSold>
      <aggregateMarketValue>14304.74</aggregateMarketValue>
      <noOfUnitsOutstanding>11545354</noOfUnitsOutstanding>
      <approxSaleDate>11/04/2025</approxSaleDate>
      <securitiesExchangeName>NASDAQ</securitiesExchangeName>
    </securitiesInformation>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>11/04/2025</acquiredDate>
      <natureOfAcquisitionTransaction>Option Granted - 05/01/2020</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>363</amountOfSecuritiesAcquired>
      <paymentDate>11/04/2025</paymentDate>
      <natureOfPayment>Cash</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>N</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>Paul Feenan</name>
        <address>
          <com:street1>3 Orchard Place</com:street1>
          <com:city>London</com:city>
          <com:stateOrCountry>X0</com:stateOrCountry>
          <com:zipCode>3 Orchard</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <saleDate>10/02/2025</saleDate>
      <amountOfSecuritiesSold>1091</amountOfSecuritiesSold>
      <grossProceeds>47034.10</grossProceeds>
    </securitiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>Paul Feenan</name>
        <address>
          <com:street1>3 Orchard Place</com:street1>
          <com:city>London</com:city>
          <com:stateOrCountry>X0</com:stateOrCountry>
          <com:zipCode>SW1H 0BF</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <saleDate>10/03/2025</saleDate>
      <amountOfSecuritiesSold>1105</amountOfSecuritiesSold>
      <grossProceeds>55448.57</grossProceeds>
    </securitiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>Paul Feenan</name>
        <address>
          <com:street1>3 Orchard Place</com:street1>
          <com:city>London</com:city>
          <com:stateOrCountry>X0</com:stateOrCountry>
          <com:zipCode>SW1H 0BF</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <saleDate>10/06/2025</saleDate>
      <amountOfSecuritiesSold>1158</amountOfSecuritiesSold>
      <grossProceeds>56952.41</grossProceeds>
    </securitiesSoldInPast3Months>
    <securitiesSoldInPast3Months>
      <sellerDetails>
        <name>Paul Feenan</name>
        <address>
          <com:street1>3 Orchard Place</com:street1>
          <com:city>London</com:city>
          <com:stateOrCountry>X0</com:stateOrCountry>
          <com:zipCode>SW1H 0BF</com:zipCode>
        </address>
      </sellerDetails>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <saleDate>10/13/2025</saleDate>
      <amountOfSecuritiesSold>8000</amountOfSecuritiesSold>
      <grossProceeds>467076.56</grossProceeds>
    </securitiesSoldInPast3Months>
    <noticeSignature>
      <noticeDate>11/04/2025</noticeDate>
      <signature>/s/ Gary Redman, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Paul Feenan </signature>
    </noticeSignature>
  </formData>
</edgarSubmission>
