Robert Walter, the MP for Dorset North, has written a letter to Lord Walker, the elite club's chairman, stressing that "equality for all" was "central to our common sense policy".
"I find it impossible to remain a member of a club that aligns itself with the Conservative Party yet refuses to offer equal status to women. It is totally unacceptable that an institution that covets its position at the heart of the Tory party should continue to exclude women," the party's Wales spokesman said.
Members of the Carlton Club have met twice in the past year to vote on whether to offer full membership to women. On both occasions the proposal secured the support of more than half of those who voted, but did not have the two-thirds majority required by the club's rules.
Mr Walter urged the club's political committee to hold a fresh ballot on the issue, but Lord Walker, a former Cabinet minister, made it clear that it was too difficult an issue to be addressed again at this point.
The decision to resign by Mr Walter, a member of the Carlton Club for 18 years, will put huge pressure on William Hague to respond to its refusal to allow women members.
Other MPs who have resigned their membership in protest include Douglas Hogg, the former Cabinet minister. "He thought that the refusal to give women full membership was totally unacceptable. His sister is a high flyer in the judicial world and he felt it was absurd not to allow her to become a member," a friend said yesterday.
Mr Hague has already warned that the Carlton Club must change its rules or lose him as a member. "The Carlton is not just a gentlemen's luncheon club. It is one of the homes of the Conservative Party. It is just not acceptable that a club in that position does not admit women as full members.
"There is no point in me going round the country saying we should have more women candidates and bring more women into the Conservative Party and then say, `Sorry, women can't join the Carlton Club'," he told the Independent last year.
All Conservative leaders are members of the St James's club, founded after the Tory defeat of 1832. Baroness Thatcher had an honorary membership.Reuse content