Defence minister Ben Wallace says he will stand down at the next election.
Mr Wallace, the longest-serving Conservative defence secretary, said in an interview with The Times: “I’m not standing next time.”
He added that he will not be resigning “prematurely” and forcing a by-election.
Mr Wallace also confirmed he would leave the cabinet at the next reshuffle, which is expected to be held this autumn.
It comes after Sky News reported that he was considering the move.
Speculation about the defence secretary’s fate has been mounting for weeks, with officials inside the Ministry of Defence wondering who might replace him.