Mr Johnson's latest intervention - proposing measures calculated to appeal to Tory voters - will fuel speculation about his leadership ambitions.
"And the reason is simple: Northern Ireland, and the insanity of the so-called "backstop".
The Tory MP and ex-army officer Tom Tugendhat, who chairs the foreign affairs committee, said: A suicide bomber murdered many in the courtyard of my office in Helmand.
He said: 'We have managed to reduce the great British Brexit to two appalling options: either we must divide the Union, or the whole country must accept EU law forever'. "Comparing the PM to that isn't amusing'".
And he condemned her vow to do whatever it takes to avoid border checks in Ireland, saying it was "insanity" and left Britain open to "perpetual political blackmail". The home secretary, Sajid Javid, said there were "much better ways to articulate your differences", telling BBC One's Andrew Marr Show that politicians should "use measured language".The housing secretary, James Brokenshire, told Sky News's Sophy Ridge on Sunday: "I think he is wrong on this".
As many prisoners as possible should be given telephones in their cells, Justice Secretary David Gauke has told the Sunday Telegraph.
The Times leads on allies of Mr Johnson claiming there was a "sanctioned hit operation" being orchestrated by Number 10 after he claimed Theresa May's Brexit strategy was like a "suicide vest".
Appearing on the BBC's Andrew Marr Show on Sunday, Javid criticised the former foreign secretary after he wrote in the Mail On Sunday that Theresa May had put the United Kingdom constitution in a "suicide vest" and handed the detonator to Brussels' chief negotiator Michel Barnier. If it isn't now, I will make sure it is later'.
Johnson has become a thorn in the side of May since he resigned as foreign minister over her Brexit plan, using newspaper columns to pressure her government over everything from social and fiscal policy to Britain's departure from the European Union in what some lawmakers see as a leadership bid.
Carolyn Fairbairn, head of business group the Confederation of British Industry, said today that a no-deal Brexit would be a "catastrophe" that would leave thousands of businesses unsure whether they could continue trading with Europe.
There has also been a renewed focus on Johnson's private life following the announcement that he has separated from his wife Marina Wheeler and the couple are divorcing.
The Sunday Express reports an ex-KGB officer who claims Russian Federation told him to kill dissidents in a similar way as was seen in the attack on the Skripals in Salisbury.
While Tory MP Alistair Burt added: 'I'm stunned at the nature of this attack.
"I don't think analogies like that are particularly appropriate". The paper says the BBC and ITV are gearing up to "go to war" again over the autumn. "Personally I hope that won't happen".