Brexit news - LIVE: EU slaps down Boris Johnson plans as Corbyn's team rage over no-deal claims

A Boris Johnson premiership would be an “opportunity for disaster” with Britain facing its most “perilous” state for decades over Brexit, the former head of the civil service has warned. 

Lord Kerslake delivered the scathing verdict as he claimed the Conservative leadership frontrunner’s promise to take Britain out of the EU by Halloween with or without a deal “is a complete hostage to fortune”.

By tying himself so emphatically to delivering Brexit by the 31 October, Lord Kerslake said Mr Johnson had put himself in the position of an escapologist who had put on a “straitjacket, padlocked the door and started the tap running”. 

Jeremy Hunt has said that he is the Tory leadership candidate who can be trusted to get a Brexit deal with the EU, in an apparent swipe at rival Boris Johnson, reports political editor Andrew Woodcock.

In an interview with the BBC’s Laura Kuenssberg, the foreign secretary said that Tory voters must make a judgment on the contenders’ “personality” and warned that if the UK sent “someone where there’s no trust” to talks, there would be “no negotiation, no deal”.

Mr Hunt denied that he was questioning the trustworthiness of his predecessor as foreign secretary, who has frequently infuriated Brussels, but his comments will be seen as a warning that the former London mayor’s character may get in the way of a smooth and orderly Brexit.

The proposers of hi-tech solutions to avoid Irish border checks after Brexit, backed by Boris Johnson, have admitted they have no idea what they would cost.

Quizzed by MPs, the head of the Prosperity UK think-tank denied the annual bill would be £13bn, but acknowledged: “We don’t have a figure.”

The stance was criticised by one MP on the Commons Northern Ireland committee who told Shanker Singham: “Somewhere you must have made a calculation of the cost?”

Liam Fox has slapped down Boris Johnson over his claim Britain could use international world trade rules to continue tariff-free trade with the European Union (EU) in the event of a no-deal Brexit.

Mr Johnson argued on Tuesday that a provision under the General Agreement on Tariffs and Trade - known as Gatt 24 - could be used to avoid tariffs under World Trade Organisation (WTO) rules for up to 10 years.

But the international trade secretary, a Brexiteer who is backing Jeremy Hunt for the leadership, said that would require the agreement of the EU, which Brussels had made clear would not be forthcoming.

"In order to benefit from the terms of Article 24, there must be an agreement between two WTO members as to the elimination of duties and other restrictive regulations on substantially all trade," he said in an article posted on LinkedIn.

"Therefore, Article 24 would not, by itself, allow the UK to maintain tariff-free trade with the EU in the absence of a negotiated agreement."

The Conservative Party confirmed yesterday morning that the result of the leadership election will be announced on 23 July. At that point, the party will have a new leader, but we had to wait until the afternoon for a No 10 spokesperson to confirm that the new leader wouldn’t take office as prime minister until the following day.

Prime Minister's Questions is about to start - ahead of Theresa May travelling to the G20 summit in Japan. 

International Development Secretary Rory Stewart, who was eliminated from the Tory leadership contest last week, has called on Boris Johnson to clarify his "do or die" remarks about Brexit.

He told the Press Association: "It was a very strange phrase to say 'do or die' because it's taken from that Tennyson poem (The Charge of the Light Brigade).

"I'm a little bit troubled by that. I hope he's not setting it up in those kinds of terms. I don't quite understand why he would agree with that kind of language.

"What I would hope he meant and I'd hope he'd clarify and say is that he's going to try to deliver a Brexit that works for Britain ... that this isn't some sort of charge towards the guns."

Leadership contender Jeremy Hunt is currently being interviewed by Jeremy Vine on BBC Radio 2, and warns Boris Johnson's promise to deliver Brexit by 31 October "do or die" risks a general election.

The phrase I should use is a fake promise - I am more likely to get us out of the EU by 31 October. If we do it in this do or die way the risk is we'll just trip into a general. We'll have Corbyn in Downing Street and no Brexit at all."

He also repeats that he would vote to Leave the European Union in a fresh referendum. 

Pressed on whether he is the richest member of the cabinet, Jeremy Hunt is pretty defensive. He says: "I don't think we should go into the politics of envy - you brought up that fact, which may or may not be true I've no idea. A lot of people would say if we start labelling people .... then we are not going to be a successful country because we have to encourage people who take risks and set up businesses."

Jeremy Hunt: "When I was elected as an MP in 2005 my big passion was lambada dancing - I have to say though this is a dance for single people and it's quite an intimate dance. Perhaps not one for the married listeners. 

Jeremy Vine: "OK - I'm intrigued. We now have that image."