Robert Peston

Boris Johnson's Brexit offer to the EU is not dead on arrival - but it may well be dead within the next 48 hours. And that could become clear as Michel Barnier, the EU's chief negotiator, briefs EU ambassadors and MEPs about what he sees as the deficiencies of the proposals. The biggest hole, as you would expect, is that EU government heads are being asked to take on trust that all the legal and technical preparations necessary for checks on goods and food flowing from Great Britain to Northern Ireland, and all the legal and technical preparations for customs checks away from the Northern Ireland border, will be completed by the end of 2021 at the very last.

The prime minister is about to launch himself on the most important and arduous challenge of his time in office, and arguably of his life. In the course of just the next five days he will try to secure a Brexit deal from an EU deeply sceptical he is prepared to make the compromises they say they need, and with a British Parliament largely hostile to his vision of life outside the EU. As I mentioned yesterday, he’ll announce the big headline of what he wants in his conference speech tomorrow.

There is only one speech that matters this week, here in Manchester at Tory party conference. It will be Boris Johnson’s on Wednesday and it will be significant – potentially historic – for what he has to say about how and whether he hopes to break the impasse with Brussels on negotiating an alternative to the Northern Ireland backstop and therefore strike a new deal to leave the EU. Intriguingly, perhaps weirdly, cabinet ministers are ebullient with optimism that Johnson is on the verge of striking a deal with Juncker and Barnier that is sellable to most Tory MPs, Northern Ireland’s DUP and even enough Labour MPs to carry it across the line in a Commons vote.

Dame Margaret Beckett – the former Labour deputy leader and ex-foreign secretary – is emerging as the most likely compromise candidate to be caretaker prime minister, according to sources involved in opposition talks about ousting Boris Johnson. As I mentioned last week, the Scottish National Party would be prepared to accept Jeremy Corbyn as temporary PM, with the express purpose of securing a three month Brexit delay and holding a general election. But it has become clear in talks between the opposition parties that the Lib Dems and expelled or self-exiled Tory MPs won’t agree to install Corbyn as PM. "We cannot win a vote of no confidence if Corbyn is the candidate," said a senior opposition MP.

There is probably now just a week or so from the end of the Tory conference for Boris Johnson to make a breakthrough on a Brexit deal, or for talks to end. Why? Well, government sources tell me the EU Commission has been told by British negotiators in no uncertain terms that Johnson will not quit to avoid being forced by the Benn Act to ask for a Brexit delay. And Brussels was also told that if Johnson is still prime minister on October 19, he will find a way to get round the law and refuse to ask for a delay. So Barnier and Juncker have literally no time to decide if Johnson is bluffing and if there is scope for backstop compromise.

The Scottish National Party has come round to the idea that Jeremy Corbyn may shortly have to become temporary caretaker prime minister, in order to prevent a no-deal Brexit on 31 October and immediately afterwards hold a general election. A source close to the SNP leadership tells me that Ian Blackford, leader of the SNP in Westminster, and Nicola Sturgeon, Scotland's First Minister, are deeply concerned that it may now be impossible to prevent a no deal Brexit unless Boris Johnson is removed from office. One said: "It is increasingly clear that we will have to install a new prime minister via a vote of no confidence, so that we can request a delay to Brexit and hold an election.

Boris Johnson wants a general election now. Jeremy Corbyn and Nicola Sturgeon both say they want an election but not till after they are sure that the provisions of the Benn Act have been effective and the UK is NOT leaving the EU without a deal on October 31. As far as I can see the only way for Johnson to break the impasse is for him to do precisely the opposite of what he has promised. He should request a Brexit delay from the EU – and for the explicit purpose of fighting an election to determine whether or not the British people would give him a mandate for a no-deal Brexit.

There is no precedent for the Supreme Court finding that a PM acted unlawfully when advising the serving monarch. There is no precedent for the Supreme Court ruling that an order in the Privy Council to prorogue parliament is null and void. There is no precedent at all for the august and magisterial ceremony in parliament that sends MPs and Lords home being ruled by judges as a pointless exercise that should now be viewed as never having taken place. There is no precedent for judges to have ruled that parliament is in effect still sitting, that legislation that had been thought to have been lost is in effect still alive, after MPs and Lords had been told by the PM that their services were not required for five weeks.

In the next election, as in the last one, McDonnellism will prove a serious challenge to the Tories. John McDonnell, as chancellor, confirmed that in government, he and Jeremy Corbyn would make a full frontal attack on 40 years of economic and industrial orthodoxy, the precepts that markets know best and that our prosperity depends on trusting the private sector. During the first 30 years, this orthodoxy may have delivered relatively steady income growth for the economy as a whole. But over the full 40 years, we've seen the greatest shift in history between the share of national income that accrues to workers and what is taken by the owners and providers of capital.

Welcome to Labour’s Twilight Zone, its ruling NEC, whose members don’t know whether they have or haven’t approved a draft policy statement in favour of a referendum combined with militant agnosticism on Leave versus Remain. Some members of the NEC said they opposed the policy, because they see it as a backdoor route - orchestrated by Milne, McCluskey and Murphy - to move the party towards becoming a Brexit party all over again. Yesterday the NEC chair Wendy Nichols asked for amendments to the statement. There were too many for a compromise to be found. Another meeting was scheduled for 8am this morning, and then summarily cancelled after 11pm last night.

At the close of Supreme Court proceedings on Thursday, there was quite a lot of to and fro about what it would actually mean if the judges find the prime minister unlawfully misled the Queen when proroguing parliament. Which was understandably interpreted by some knowledgeable observers as a signal that the judges may indeed find that Boris Johnson unlawfully prevented MPs from sitting at this critical time for the UK. The big issue they have to decide is whether they have a locus at all, whether the PM’s use of the royal prerogative to send MPs home for five weeks is - in the jargon - justiciable, or an issue for any court. The consensus among lawyers is that those arguing for the prosecution, Pannick and O’Neill, had the best of this argument.

The shape of the Brexit fix that Boris Johnson wants from the EU’s 27 leaders is now clear.

I am told Jean-Claude Juncker learned just one thing from Boris Johnson on Monday in Luxembourg. In the words of one of his colleagues there was "confirmation that the UK (under Johnson) wants more of a border on the island of Ireland than the previous government". Which is the nutshell of the whole of what the PM seeks qua new deal and what the EU’s 27 leaders need to evaluate either as deft compromise or as brutal betrayal of Dublin and the Good Friday Agreement. This dispute harks back to the December 2017 joint agreement between the UK and EU which pledges to prevent the creation of "a hard border including any physical infrastructure or related checks and controls".

Has any member of Cabinet seen the full legal advice given to the Prime Minister, which persuaded Johnson proroguing or suspending parliament is lawful? Julian Smith asked for it, on the day Cabinet was bounced into agreeing prorogation. Amber Rudd asked for it subsequently. I am not aware that either got it. Instead they received a 'trust me' from Boris Johnson. This could be a problem for him and ministers because the ministerial code, amended after Chilcott Enquiry into the legality of going to war in Iraq, says all ministers have right to see full legal advice – not just summaries – on all contentious issues. Will Cabinet now get the advice after today’s Court of Session judgement?

Very important breaking news. Which is that trade unions, in their TULO meeting with Jeremy Corbyn, have tonight endorsed the Labour leader's position that in a general election Labour should campaign for a referendum that would have a "credible leave option and remain" on the ballot paper. The reason this matters is that those senior members of the shadow cabinet, such as Keir Starmer, Emily Thornberry, John McDonnell and Tom Watson, who want Labour to adopt an unambiguous remain position have been defeated. "It is important that voters who want to leave as well as those who want to remain can vote Labour. What we've rejected is the Trumpian no-deal position of Boris Johnson".