Boris Johnson has privately pleaded with at least 30 potential rebels in a bid to head off a leadership challenge, while allies have set up a 100-strong “save Boris” WhatsApp group, The Telegraph understands.

Several of the Prime Minister’s most loyal supporters are running a “shadow whipping operation” to bring wavering MPs back on side. They are telling rebels they do not have enough support on the Tory benches to reach the 54 letters of no confidence required to mount a challenge.