Rory Stewart, the international development secretary, and up to a dozen ministers are expected to quit

As many as six Conservative MPs are due to hold talks with the Liberal Democrats this week with the aim of derailing Brexit and Boris Johnson’s premiership.

Sources close to the talks say the discussions will include the possibility of a vote of no confidence in Johnson or even the option of Tory MPs defecting to the anti-Brexit party.

If only two were to switch, it would immediately deny Boris Johnson a parliamentary majority if, as expected, he is named Conservative leader on Tuesday.

Sir Ed Davey, who served as Lib Dem energy minister in the coalition cabinet with leading Tory remainers, is understood to have been approached by Conservatives desperate to stop Johnson.

Sources close to the Lib Dem leadership hopeful said: “Boris