The UK’s chief civil servant, Simon Case, has resigned his membership from the men-only Garrick Club, Sky News understands.

It comes following criticism of his membership of the organisation due to its restrictive entry requirements.

Asked about his membership on Tuesday, Mr Case said: “I have to say, my position on this one is clear, if you believe profoundly in reform of an institution, by and large it is easier to do if you join it and make the change from within rather than chuck rocks from the outside.

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“And by the way, maths is also part of this.

“Every one person who leaves who is in favour of fixing this antediluvian position, every one of us who leaves means these institutions don’t change.

“I think when you want reform you have to participate.”

A list of members of the club was recently published by The Guardian newspaper, which included the King, Deputy Prime Minister Oliver Dowden and Sir Richard Moore, the head of MI6.

Jill Rutter, a former civil servant and now a part of the UK in a Changing Europe thinktank, criticised Mr Case’s previous defence of his membership.

She said: “Simon Case casts himself as Garrick fifth columnist leading an army of militant public servants who have just joined to change the rules to admit women.

“[I] am wondering how impressed his female colleagues are by this noble sacrifice.”

Labour MP Liam Byrne, said on social media: “I’m afraid any good the cabinet secretary may have sought ‘reforming the Garrick from the inside’ is well outweighed by the bad of our Civil Service chief indulging in membership of an elite all male club.”

According to the club’s website, the Garrick “has around 1,300 members including many of the most distinguished actors and men of letters in England”.

It goes on: “The original assurance of the committee, ‘that it would be better that ten unobjectionable men should be excluded than one terrible bore should be admitted’, ensures that the lively atmosphere for which the club was so well-known in the nineteenth century continues to invigorate members of the club in the twenty-first century.”

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