Questions over Theresa May's leadership have been raised again as a newspaper report on Sunday suggested three top Tory MPs are being lined up to replace her.
It comes just days after May was forced to state "I'm not a quitter" on a trip to China, dismissing criticism from within her own party.
A rift in the Tory party over Brexit has been threatening to break into the open for some time, with the Whips Office promising disgruntled MPs an imminent announcement on post-Brexit trade to placate them.
Johnson and Gove had both been jostling for the Tory top job when May replaced David Cameron as leader and PM in the wake of the EU referendum in 2016 and both are believed to still hold leadership ambitions.
Rees-Mogg, a vocal supporter of Brexit, yesterday accused the Treasury of "fiddling the figures" on leaked forecasts about the economic impact of Britain leaving the EU. He was appointed to lead the European Research Group at the start of the year, a group of pro-Brexit Tory MPs scrutinising the government's handling of Brexit.
Meanwhile, a senior Tory and arch Brexiteer today accused ministers if being "vague" and "divided" over Brexit. Bernard Jenkin, writing in the Telegraph, singled out chancellor Philip Hammond for criticism, saying he must back the PM.
Hammond was slammed over comments last week that Brexit would bring only "modest" changes, by Rees-Mogg.
"If the Prime Minister sticks to one policy and the chancellor keeps advocating another, what are officials meant to do?" said Jenkin.