The head of the civil service has quit an all-male private members’ club just a day after being questioned by MPs about his involvement in the institution.

Cabinet Secretary Simon Case is understood to have renounced his membership of the Garrick Club, despite having claimed to MPs that he was working to reform it from within.

At a parliamentary committee on Tuesday, Mr Case suggested it was “easier” to change the all-male organisation “from within rather than chuck rocks from the outside”.

His comments come after The Guardian said it had published the Garrick Club’s membership list, which it claimed included the King, Deputy Prime Minister Oliver Dowden and Sir Richard Moore, the head of MI6.

The Guardian reported that spymaster Sir Richard has also quit the club.

While giving evidence to MPs, Mr Case was asked by Labour’s Liam Byrne whether he could “foster a genuine culture of inclusiveness” in the civil service “while being a member of an all-male club”.

I think when you want reform you have to participate

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.

“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.”

He added: “I’m very sure I speak on behalf of all the public servants who have recently joined the Garrick under the banner of trying to make reform happen.”

Mr Case, who works closely with Prime Minister Rishi Sunak, stepped back from his Cabinet Secretary duties in October because of a medical matter, before returning to work in January.

Before being appointed Cabinet Secretary by former prime minister Boris Johnson in 2020, Mr Case served as private secretary to the then-Prince of Wales.