Boris Johnson urges Tory MPs to back changes to Brexit deal amid fears of rebellion

Former prime minister Gordon Brown denounces ‘act of self-harm’

Boris Johnson has pleaded with fractious Tory MPs to back him in his bust-up with Brussels, amid Downing Street fears of a backbench rebellion against measures which ministers admit break international law.

In a Friday evening video conference call, the prime minister sought to answer deep anxieties over provisions in his UK Internal Market Bill which have been condemned by three former prime ministers and provoked Brussels to threaten legal action.

Senior and normally loyal Tories have vowed to vote against the government when the bill is rushed through the Commons next week, and while privately some were doubtful of mustering the 40 or more rebels needed to block the legislation, it then faces likely defeat in the House of Lords.

Mr Johnson’s decision to give UK ministers powers to override the provisions of his own Brexit divorce agreement on tariffs, state aid and customs procedures for Northern Ireland led the European Commission to issue an ultimatum to back down or put talks on a trade deal at risk.

The PM told around 250 MPs that controversial clauses in the bill are "necessary to stop a foreign power from breaking up our country", and maintained there is still a good chance of getting a trade deal with the EU.

With senior Conservatives planning to amend the legislation, he was also said to have warned them against going "back to the miserable, squabbling days of last autumn". But during the call, which suffered connection issues and saw no questions taken by Mr Johnson, further fall-out emerged from the EU.

Leaders in the European parliament said they would "under no circumstances ratify" any trade deal reached if "UK authorities breach or threaten to breach" the Withdrawal Agreement.

And Mr Johnson appeared not to have ended the disquiet within his party during the call, with senior backbencher Sir Bob Neill saying he was not reassured by the speech.

Sir Bob, who chairs the Commons Justice Committee and is tabling an amendment to the Bill which he says would impose a "parliamentary lock" on any changes to the Withdrawal Agreement, said he still contends it contains "objectionable" elements.

"I believe it is potentially a harmful act for this country, it would damage our reputation and I think it will make it harder to strike trade deals going forward," he told Channel 4 News.

The UK side is understood to be ready to keep talking even if Brussels is suing the UK for breach of an international treaty, but continues to demand “realism” from EU negotiators on issues like state aid and fisheries.

On fisheries, a senior UK negotiating official insisted that “huge change” was still needed from Brussels in order to get an agreement, which Mr Johnson insists must be concluded by 15 October.

Labour’s former PM Gordon Brown on Friday described the threat to break international law as  “a huge act of self-harm” and said he feared Mr Johnson was leading the UK into “battle with Europe for years ahead” which would damage national prosperity. His comments followed warnings from fellow ex-premiers Sir John Major and Theresa May that the UK risks forfeiting the “trust” necessary to strike future deals with countries around the world.

And former Conservative leader Michael Howard, a leading advocate of Brexit, said that Mr Johnson was effectively proposing to “renege” on his treaty with the EU.

“That’s not something a British government should do,” Lord Howard told Sky News. “There is no mandate from the British people to break treaties.”

An amendment tabled by Tory former minister Sir Bob and backed by Ms May’s deputy prime minister Damian Green would place a parliamentary brake on provisions overriding the withdrawal agreement, by requiring a separate Commons vote to approve the date on which they would take effect.

But some rebels wanted to strike out any suggestion that the UK was ready to go back on a treaty negotiated and signed by the prime minister and hailed by him less than a year ago as a “great” and “oven-ready” deal.

Veteran backbencher Sir Roger Gale told The Independent that there was “a great deal of anger” among Tory MPs, who were picking up “very hostile” responses to the PM’s plans from Conservative voters.

“It’s a matter of principle,” said Sir Roger. “If you sign an agreement, you honour that agreement. This country has had a long and proud tradition of playing it straight.

“It comes down to the difference between right and wrong and I’m not sure that Downing Street knows the difference any more. Even if it is just sabre-rattling, it is a very dangerous game because it is damaging our reputation internationally.”

The cross-party House of Lords Constitution Committee - whose members include two Conservative former Northern Ireland ministers as well as the eminent QC Lord Pannick, who took on the government in last year’s Supreme Court battle over prorogation – wrote to Lord Chancellor Robert Buckland to demand a statement on why he believes the bill is compatible with the UK’s obligations under international law.

In a letter signed by chair Baroness Taylor, the committee wrote:   “Any breach of international law threatens to undermine confidence in future treaty commitments made by the UK government and increases the likelihood that the governments of other countries would not comply with their international law obligations”.

Meanwhile, disquiet among civil servants was reflected in a barbed memo from the departing head of the government’s Legal Department, Sir Jonathan Jones, who is working out his notice after quitting last week in protest at the bill.

Writing to hundreds of government lawyers, Sir Jonathan said that the new head of the civil service Simon Case – appointed by Mr Johnson as his cabinet secretary this week – had issued a ruling that “notwithstanding the breach of international law”, ministers and officials would be operating within the terms of their codes of conduct when working on the bill.

The outgoing Treasury solicitor pointedly noted that many government lawyers are “rightly interested” in the legal and constitutional issues surrounding the bill, and suggested that anyone with questions about the advice from Mr Case and attorney general Suella Braverman should raise their concerns with their line managers.

Exasperation in European capitals at Mr Johnson’s approach surfaced in a tweet from German ambassador to London Andreas Michaelis, who said: “In more than 30 years as a diplomat I have not experienced such a fast, intentional and profound deterioration of a negotiation. If you believe in partnership between the UK and the EU like I do then don't accept it.”

But sources on the UK side played down the prospects of an imminent collapse of the talks process, insisting that progress had been made in talks this week between Mr Johnson’s chief negotiator David Frost and the EU’s Michel Barnier.

“Talks this week have been relatively more constructive than you might expect, but ultimately progress will be determined by whether we get more realism from them on the key areas of divergence,” said a senior UK negotiating official.

“Whilst we are beginning to get discussions of substance of some issues, big important areas remain unresolved. We will carry on talking in Brussels next week.

“On subsidies we are asking that the EU agree with us what they have agreed with so many others in this area.

“Despite their insistence to the contrary, on fisheries their position is still a long a way from the huge change we need to get an agreement.”

London is furious at Mr Barnier’s public confirmation in comments following Thursday’s talks that Brussels may withhold “third party” status from the UK after the end of the Brexit transition in January because of “uncertainties” about standards of animal health and sanitation once it stops following EU rules.

The move would prevent the export of £5bn worth of food products a year to areas covered by the EU’s sanitary regulations, which crucially include Northern Ireland. It was this threat which prompted Mr Johnson’s explosive intervention this week.