Sir Geoffrey Clifton-Brown voted for a motion expressing confidence in the Government on Monday.
Unusually, the vote was tabled by the Government because it refused to accept the wording of a Labour motion after Boris Johnson announced he was staying on as Prime Minister until the autumn.
MPs were asked whether "this House has confidence in Her Majesty's government", with defeat almost certainly triggering a general election.
The Cotswolds MP voted for the motion alongside North Wiltshire MP James Gray and almost all their Conservative colleagues, as it was passed 349-238.
Voting for the motion were 342 Tory MPs, six DUP MPs and one Independent MP.
Meanwhile, 181 Labour MPs, 37 SNP MPs, 12 Lib Dem MPs made up the majority of those voting against.
Boris Johnson has stripped the Tory party whip from MP Tobias Ellwood after he failed to support the Government in the vote.
Mr Ellwood, a former minister who chairs the Commons Defence Committee, argued he was unable to travel back from a meeting with the president of Moldova because of “unprecedented disruption”.
But he will now no longer be able to vote in the leadership contest.
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