Scottish Tory MPs have plunged Theresa May into a fresh crisis over her Brexit deal, by warning they will rebel if it leaves the UK tied to EU fishing rules.

All 13 Conservatives north of the border – including David Mundell, the Scottish secretary – signed a hand-delivered letter to the prime minister, as she began her crunch cabinet meeting.

It was sent after reports that the draft agreement will park the controversy over fishing rights until the negotiations on a future trade deal, which won’t start until next year.

In the letter, Mr Mundell and his 12 fellow Tories said Ms May had promised Britain would have “complete control and full sovereignty over domestic waters”, from the end of 2020, when the transition period ends.

It reads: “We could not support an agreement with the EU that would prevent the UK from independently negotiating access and quota shares.

“That would mean that we would not be leaving the CFP [commons fisheries policy] in practice and would be becoming an independent coastal state in name only.”

The letter sparked fresh speculation that Mr Mundell is poised to resign unless the prime minister backs down and seeks better terms on fishing rights in the draft deal.

Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Show all 14 1 /14 Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Internal divisions in the Conservative Party have exploded into a bitter public row over Boris Johnson‘s “disgusting” criticism of Theresa May. Some senior Tories furiously denounced the former foreign secretary after he accused the prime minister of having ”wrapped a suicide vest” around Britain Reuters Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Sajid Javid, Home secretary Sajid Javid, the home secretary, rebuked his former cabinet colleague and said: “I think there are much better ways to articulate your differences.” He told the BBC’s Andrew Marr Show that the public wanted politicians to use “measured language” BBC/PA Boris Johnson 'suicide vest' Brexit jibe causes Tory divide But other MPs leapt to Mr Johnson’s defence, as dividing lines ahead of a possible leadership contest begin to take shape. The Uxbridge MP has repeatedly criticised Ms May’s Chequers plan and used a newspaper article on Sunday to suggest it amounted to “wrapping a suicide vest around the British constitution”. His latest salvo at the prime minister prompted immediate condemnation, with one minister publicly vowing to end Mr Johnson’s career over the matter PA Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Alan Duncan, Foreign minister Alan Duncan, a foreign minister who worked in Mr Johnson’s team for two years, wrote on Twitter: “For Boris to say the PM’s view is like that of a suicide bomber is too much. This marks one of the most disgusting moments in modern British politics. “I’m sorry, but this is the political end of Boris Johnson. If it isn’t now, I will make sure it is later.” Getty Boris Johnson 'suicide vest' Brexit jibe causes Tory divide James Brokenshire, Housing secretary Housing secretary James Brokenshire added his voice to the criticism, calling Mr Johnson’s comments ”wrong” He said: “I think he is wrong on this...I think the tone that he has used isn’t right and I think that we just need to be very focused on actually moving forward with the Chequers plan.” AFP/Getty Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Zac Goldsmith But as Tory hostilities spilled over into open public warfare, Richmond Park MP Zac Goldsmith, an ally of Mr Johnson, hit back at Mr Duncan. He wrote: “There are a number of possible motives behind this tweet, but given its author, we can be certain ‘principles’ aren’t one of them.” Getty Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Jacob Rees-Mogg Senior Tory Brexiteer Jacob Rees-Mogg told The Independent he thought Mr Johnson’s “suicide belt” accusation was little more than “a characteristically colourful catchphrase”. He added: “I agree with the sentiment. The criticism of Boris’s wording merely serves to highlight his point. It means more people hear of Boris’s criticism of Chequers and many will agree with him.” Reuters Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Nadine Dorries Nadine Dorries, another Brexit supporter, said Mr Johnson’s opponents were “terrified of his popular appeal”, adding: “Don’t underestimate the vitriol that’ll be directed towards Boris today. He delivered the Leave vote, Remainers and wannabe future PMs hate him.” If Mr Johnson became leader and prime minister he would deliver a “clean and prosperous” Brexit, she said Rex Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Andrew Bridgen Andrew Bridgen said Ms May was to blame for her leadership problems. Asked if Mr Johnson had put a bomb under her leadership, Mr Bridgen said: “I think that Theresa May did that herself when she put forward the Chequers proposals without consulting widely prior to that.” Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Steve Baker, former Brexit minister Steve Baker, the former Brexit minister, warned Ms May the Conservatives faced a "catastrophic split" if she did not jettison her Chequers plan. Mr Baker, who quit the government in July over the scheme, said: “When negotiating, the prime minister needs to demonstrate her intent and also her power to deliver. "If we come out of conference with her hoping to get Chequers through on the back of Labour votes, I think the EU negotiators would probably understand that if that were done, the Tory party would suffer the catastrophic split which thus far we have managed to avoid.” But he insisted he did not want a change in the Conservative leadership, saying Brexiteers did “not want to be in a position of conflict with our own prime minister” Reuters Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Tom Tugendhat The deep divisions on the Tory benches were laid bare as Tom Tugendhat, who chairs the Commons foreign affairs committee and is a possible leadership rival to Mr Johnson, also hit out at the former foreign secretary. Recalling how he encountered a suicide bomber in Afghanistan during his time in the army, Mr Tugendhat told Mr Johnson to “grow up”. He said: “A suicide bomber murdered many in the courtyard of my office in Helmand. The carnage was disgusting, limbs and flesh hanging from trees and bushes. Brave men who stopped him killing me and others died in horrific pain. “Some need to grow up. Comparing the PM to that isn’t happy.” PA Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Alistair Burt Alistair Burt, another Foreign Office minister who worked in Mr Johnson’s team, said: “I’m stunned at the nature of this attack. There is no justification for such an outrageous, inappropriate and hurtful analogy. “If we don’t stop his extraordinary use of language over Brexit, our country might never heal. Again, I say, enough.” AFP/Getty Boris Johnson 'suicide vest' Brexit jibe causes Tory divide It comes amid that Ms May’s former aides drew up a dossier on Mr Johnson’s sexual encounters with the aim of undermining his leadership prospects. The document was compiled in 2016, when the Uxbridge and South Ruislip MP was seen as the main rival to Ms May in her bid to enter No 10. Downing Street and Conservative Campaign Headquaters (CCHQ) both denied having leaked the 4,000 word memo after it was circulated around Westminster AFP/Getty Boris Johnson 'suicide vest' Brexit jibe causes Tory divide Mr Johnson confirmed that his 25-year marriage to wife Marina had ended AP

The Scottish secretary – Ruth Davidson, the Tory leader north of the border – had already threatened to walk out if Northern Ireland is given preferential trading terms with the EU.

Even worse for Ms May, losing the support of the 13 Scottish Tories would make it even less likely that parliament will back the agreement, in a landmark vote expected early next month.

Pro-Brexit Tories have already joined forces with the Democratic Unionist Party (DUP) to warn the deal is doomed, with Labour also supplying the numbers to vote it down.

EU member states with big fishing industries have demanded access to British waters, in return for the UK enjoying tariff-free access to EU markets under plans for the Irish border ‘backstop’.

As a result, the controversy has been deferred until the end of the transition period, until a future UK-EU agreement is reached on reciprocal access to waters.

In the Commons, a Tory backbencher, Martin Vickers, demanded “an absolute assurance that it will be for the UK, and the UK alone, to determine who fishes in our national waters after a deal is signed”.

In response, the prime minister said: “I can reassure my honourable friend that we will become an independent coastal state, and it will be the UK negotiating on the UK’s behalf in terms of access to UK waters.”

However, Ms May did not say when the UK will regain negotiating rights – which, the Scottish Tories fear, will not be until after the start of 2021.

The Tories are under pressure because the SNP is opposing Northern Ireland effectively staying in the EU single market – to avoid a hard Irish border – while Scotland is forced to leave.