Senior Tories attempted to rally behind an increasingly beleaguered Rishi Sunak on Saturday night amid claims that some Conservative MPs are plotting to replace him with Penny Mordaunt before the next general election.

Former cabinet ministers Jacob Rees-Mogg and David Davis went public to denounce the idea as “mad” and “bonkers”, as did senior backbenchers, including former vice-chair of the 1922 Committee Sir Charles Walker.

With many backbench Tories – including some with healthy majorities – increasingly fearful of losing their seats in an election wipeout, accounts of a “plot” to oust Sunak surfaced on Saturday in the Daily Mail and the Daily Telegraph.

The Mail said MPs on the right of the party had “held talks with moderates” about uniting behind Mordaunt, the leader of the House of Commons, and anointing her as leader in a “coronation” in the coming weeks.

Mordaunt made no public comment about the claims but her supporters said she was not party to, or aware of, any such plot, and that she believed the stories were an attempt by her detractors on the right to damage any potential challenge she may make in future, after a Tory election defeat.

Several Tory MPs maintain, however, that Mordaunt has been “on manoeuvres” for months, making clear she would be happy to visit MPs’ constituencies and get to know their local party officials.