Boris Johnson has been warned the Government’s chief law officer will resign if he does not write to Brussels to ask for a Brexit extension, The Mail on Sunday has learned.

Attorney General Geoffrey Cox is understood to have conveyed the threat during a ‘heated’ exchange with the Prime Minister over the Government’s concession to a Scottish court last week that Mr Johnson would comply with the Commons’ order to ask for a delay if no deal is agreed by October 19.

The concession came despite Mr Johnson’s public assertion that he would rather ‘die in a ditch’ than make such a request.

The revelations come as EU sources revealed last night that an embattled Mr Johnson has been forced to cancel plans to meet Germany’s Angela Merkel and France’s President Macron after they refused to change their diaries in order to see him.

According to multiple sources, Friday’s Government submission to the Court of Session followed an animated encounter between Mr Johnson and his law officers – including Mr Cox and Lord Keen, Advocate General for Scotland – on Wednesday evening.

Attorney General Geoffrey Cox said he would resign if Boris Johnson does not write to Brussels to ask for a Brexit extension (Mr Cox pictured in the House of Commons)

One source said that Mr Cox and Lord Keen told the Prime Minister that, if the Government did not make clear it would not break the law, the Prime Minister would face ‘resignations’, adding: ‘Boris was absolutely furious but he had to back down.’

When the submission was made public on Friday, Mr Johnson – who has dismissed rebel legislation to request an extension as ‘the Surrender Act’ – reacted by tweeting ‘New deal or No Deal’ and insisted he would ‘Get Brexit Done’.

Mr Cox is already regarded by many Conservatives as ‘the wrecker’ who sank Theresa May’s hopes of winning Commons’ support for her Brexit deal earlier this year. At the time, even Brexit hardliners were looking for reasons to support the deal. But the Attorney General spelt out in blunt terms that the UK had no legal way out of the hated backstop.

Reports of Mr Cox’s threat come as Business Secretary Andrea Leadsom today insists in The Mail on Sunday there is ‘cautious optimism’ that a deal is within reach – despite Brussels refusing to hold talks with the UK this weekend.

Writing opposite, Ms Leadsom says: ‘If we do get a deal at the European Council on October 17 and 18, we will move at pace to get it through Parliament before October 31.’

But last night, Dutch Prime Minister Mark Rutte added to the sense of scepticism on the Continent, saying ‘important questions remain’ about Mr Johnson’s proposals.

Speaking after a phone call with Mr Johnson, he said: ‘There is a lot of work to be done ahead of October 17/18.’ The European Commission said yesterday EU members had agreed that Mr Johnson’s proposals – under which the backstop aimed at preventing a hard border between Northern Ireland and the Irish republic would be replaced by a system whereby Northern Ireland would stay in the EU single market for goods but leave the customs union – ‘do not provide a basis for concluding an agreement’. It added that the UK would be given ‘another opportunity to present its proposals in detail’ tomorrow.

Mr Cox (left) is understood to have conveyed the threat during a ‘heated’ exchange with the Prime Minister (right) over the Government’s concession to a Scottish court last week that Mr Johnson would comply with the Commons’ order to ask for a delay if no deal is agreed by October 19

Downing Street said Mr Johnson will ‘continue to hit the phones’ over the coming days and ‘remains open to meetings with EU leaders’. Brexit Secretary Stephen Barclay will travel to the Netherlands for talks later today. Mr Johnson’s chief negotiator David Frost is expected to return to Brussels tomorrow and his chief of staff, Sir Edward Lister, will travel to Dublin to try to persuade the Irish Government to drop their opposition.

No 10 regards October 16 – the day before the start of the crunch EU summit – as the final deadline for the EU to lift its opposition, giving Mr Johnson just nine days to find common ground with Brussels.

But after Mr Cox’s stand, Mr Johnson has spent this weekend holed up with advisers trying to thrash out which loophole could be used to obey the law while still sticking to his pledge that the UK will leave on October 31.

Government lawyers are trying to find a form of words for the letter which would comply with the Act, yet not persuade the EU to grant a delay. Aides are also still looking at ways of trying to ‘sabotage’ the EU from within, such as by refusing to appoint a British EU commissioner, to force them to kick us out.

During his encounter with Mr Johnson, Mr Cox is understood to have said the legal system would be destabilised if he did not comply with the so-called Benn Act, designed to force him to request an extension if no deal is done.

Mr Johnson’s chief adviser Dominic Cummings told advisers the extension letter was ‘Parliament’s letter, not the Prime Minister’s letter’ – suggesting there were way of complying with the Benn Act but delivering Brexit on time.

But a source told this newspaper that the Attorney General ‘thinks they can’t get round the Act’.

Mr Cox said last night that there was no ‘row’ when he met the Prime Minister. But asked if he had threatened to resign, he replied that he was ‘not at liberty’ to discuss any advice that he provided to the Prime Minister.

The Mail On Sunday COMMENT NOW is the moment of truth in the United Kingdom’s long struggle to extricate itself from the European Union. For years many British people have suspected that the EU is not really interested in anything except more Europe. It is almost impossible to negotiate departure from a body which has no real understanding that a member nation might wish to regain its independence, or any real belief that a such a nation should have that right. Boris Johnson has put forward plans for a compromise which are sensible and thoughtful. He has taken account of the real worries of the Irish government and people about the revival of a new hard border with Northern Ireland. These plans have growing support from all sides at Westminster, and are a realistic basis for a lasting compromise. We shall now see what the EU’s superficially emollient and smiling leaders are really made of, when the chance of a civilised, negotiated parting is placed before them. Advertisement

Junker raises hope of breakthrough

By Harry Cole

Chances of a Brexit breakthrough this month are low, but a glimmer of hope for Boris Johnson has emerged from Jean- Claude Juncker’s inner circle.

The outgoing European Commission President has told his closest aides that cutting an 11th-hour deal with Britain would cement his reputation as the ‘ultimate political fixer’.

Jean- Claude Juncker has told his closest aides that cutting an 11th-hour deal with Britain would cement his reputation as the ‘ultimate political fixer

Mr Juncker is due to step down on October 31, the day Britain is scheduled to leave the EU, meaning any delay – or a No Deal Brexit – would blight his legacy. EU sources say the outspoken Eurocrat made the remarks at a meeting of his most senior advisers last week.

However, they came before the EU widely panned Boris Johnson’s compromise offer, with hopes fading in London of a deal being cut before a possible General Election.

A source close to Guy Verhofstadt, the head of the EU’s Brexit Steering Group, said flatly last night: ‘Boris Johnson’s proposal does not have a chance. He seems to be gunning for no deal. Nothing is moving at all this weekend’.

A No10 source added: ‘Even if Juncker wanted to do a deal, it is slipping out of his control. Appointing Michel Barnier, France’s most unreasonable Frenchman, to lead the negotiations is coming home to roost.’

And yesterday, Britain’s former EU Commissioner Lord Hill said that the major roadblock to a deal was Dublin and compromise before the end of the month was a ‘stretch’. The Brussels expert told the BBC: ‘I spoke to an EU ambassador who said: “We don’t understand what the backstop is, we don’t care about the backstop, we would be perfectly happy for the Irish to drop it, but so long as they want it, we’re with the Irish,” and that’s the conundrum.’

On Friday, No10 enforcer Dominic Cummings warned colleagues that if Europe shows no signs of compromise next week, then ‘that’s it, we’re off’.

Anger as No10 halts US trade talks

By Glen Owen

Downing Street has ordered Britain’s trade negotiators to call a halt to talks with America over a post-EU deal – over fears that it might ‘spook’ Brussels and ruin the chance of a breakthrough in the Brexit impasse.

International Trade Secretary Liz Truss says that the US, Japan, New Zealand and Australia are all ready to negotiate a free trade agreement with the UK post-Brexit

Officials at the Department for International Trade (DiT) have privately expressed their frustration that No 10 is not allowing them to close a deal with Washington in case it angers the EU in the run-up to the critical summit on October 17.

The DiT has hit back by arguing that securing deals with the US and other countries would help the talks by giving them ‘leverage’ for ‘the purposes of EU negotiations’.

International Trade Secretary Liz Truss says that the US, Japan, New Zealand and Australia are all ready to negotiate a free trade agreement with the UK post-Brexit, describing them as ‘very enthusiastic trading partners’ who are ‘very keen to get started’. In America’s case, it would be the largest free trade agreement the US has ever signed with another nation. Washington’s major priority is to cut UK tariffs on steel imports, while Ms Truss is determined to secure access to the US’s market for financial services.

Ms Truss said at last week’s Tory conference: ‘There are negotiations to go through first, but we are going to be tough negotiators. This is because we are in a very strong position, we’re striking our first trade deals in 45 years, we’re the fifth largest economy in the world. We have a lot of opportunities that those other nations want to access, though it’s got to be in our interest to strike a deal.’

Ms Truss travelled to New York last month to meet her opposite number, US trade boss Robert Lighthizer – and to insist the UK will not compromise on food standards or access to the NHS as part of the deal. London and Washington have provisionally agreed to aim for a deal to be struck by July 2020 – assuming Brexit has finally been secured before then.

Back Boris's deal or Brexit will be the boxset that never ends

By Andrea Leadsom Business Secretary

After spending more than two turbulent years as Leader of the House of Commons, I have developed a pretty good sense of the mood of the House.

And the mood this week shifted to a tone of cautious optimism.

The reason for this seems clear to me.

I hope Parliament can recognise that we are on the cusp of a breakthrough – and their backing makes all the difference, writes ANDREA LEADSOM

After weeks of careful discussion, negotiation and compromise, the Prime Minister has provided a fair and reasonable offer to the EU. He has delivered on his promise to give them a proposal that addresses the problem of the backstop, but that protects the interests of the entire UK. The new deal will allow the United Kingdom to leave the EU on good and friendly terms. It meets the people’s priorities – of taking back control of our money, laws and borders. It allows us to leave the customs union and the single market.

And crucially, it protects the Irish peace process. Having recently met with some superb businesses in Belfast, to discuss Brexit readiness, I know how important it is for them to avoid friction at the border.

The offer is a compromise. It respects the integrity of the entire UK, but also of the EU’s single market. Vitally, it requires democratic consent for the special arrangements in Northern Ireland and ensures flexibility for all parties to deal with the land border between the UK and the EU.

We have always been clear that we would prefer to leave the EU with a deal, with minimum disruption and with a good UK-EU relationship. This new deal offers that, while respecting the result of the referendum.

The proposal is our opportunity to strike a deal with the EU before we leave on October 31. We will now work with Brussels in the time remaining to iron out the details. We hope they come to the table in the same spirit we have – with optimism, compromise and mutual respect.

If we do get a deal at the European Council on the 17th and 18th of October, we will move at pace to get it through Parliament before October 31.

If the EU do not want to work with us, we will have to leave anyway, without a deal. But to be clear, the worst-case scenario isn’t leaving the EU without a deal on October 31.

The worst-case scenario is postponing yet again, and prolonging the uncertainty, with our hands tied by Parliament. Expensive for businesses and totally frustrating for those who just want us to get on with it.

Delay is what Jeremy Corbyn wants. Having voted against a deal under the last Government, he then insisted he was so in favour of a deal that he was willing to delay leaving the EU.

He hampered our negotiating efforts in doing so, yet still we found a reasonable proposal – which he now refuses to accept. In fact, Corbyn rejected the deal so quickly – before the EU or Ireland had even had time to respond – that you might ask, with good reason, whether he’s actually read it!

This Government will get Brexit done so Parliament can focus on our bold domestic agenda and deliver on the people’s priorities.

I remain optimistic. I have spoken to many people on all sides of the House who welcomed the Prime Minister’s statement and his offer to meet with colleagues and discuss the proposal.

Boris Johnson has proved his detractors wrong. They chose not to take him at his word when he said he would work hard to find a deal. Now we have a proposal that the EU must engage with, he needs the backing of all MPs for the sake of the country.

I hope Parliament can recognise that we are on the cusp of a breakthrough – and their backing makes all the difference.

The public want to move on.

Businesses want to move on.

Parliament must move on.

There are many MPs who share the public’s frustration – that Brexit is like the boxset that never ends.

They agree that it’s time for the big finale, so we can move on to the next great series. And an increasing number agree that this is the sensible and workable proposal that will do just that.

Let’s get on with it!