Tory leadership debate - live: Boris Johnson challenged on ‘letterbox’ comments, as candidates quizzed on Brexit, tax cuts and climate change

Conservative members would be prepared to break up the UK, destroy the Tory Party or suffer economic damage to get the UK out of the European Union, a poll has suggested.

The YouGov survey of party members - who will decide the next prime minister - suggests almost half (46 per cent) would be happy to see the Brexit Party's Nigel Farage as their new leader.

Despite the strong support for Brexit, even if it had major repercussions, Tory members indicated they would be prepared to call it off rather than see Jeremy Corbyn enter Number 10.

The survey found 63 per cent of members would be prepared to see Brexit take place even if it meant Scotland leaving the UK.

Some 61 per cent would rather Brexit took place even if it caused "significant damage" to the economy, 59 per cent would prioritise leaving the EU even if it meant Northern Ireland breaking away from the rest of the UK, and 54 per cent would accept the Tory party "being destroyed" in order to secure Brexit.

But only 39 per cent of the members who responded to the question said they would want Brexit to take place if it meant Labour leader Mr Corbyn becoming the next prime minister, with 51 per cent saying they would rather the UK did not leave the EU in order to avoid that happening.

YouGov's Matthew Smith said: "Conservative members are not just ideologically committed to Brexit - they also genuinely believe that the failure to deliver on the result of the 2016 referendum will bring about the destruction of the party's electoral chances.

"Indeed, half (51 per cent) of members believe that Britain ending up staying in the EU after all would damage the party to the extent that it will never lead a government again, and another 29 per cent think it would put the party out of power for multiple elections to come.

"By contrast, most members believe that successfully bringing about Brexit will win the Tories at least the next election."

A third of those who watched the Channel 4 leadership debate on Sunday thought Rory Stewart performed best, an Opinium poll has found.

Among Tory voters who watched the show, 24 per cent thought Mr Stewart triumphed, narrowly ahead of Mr Hunt on 22 per cent.

Dominic Raab came third on 10 per cent, Sajid Javid had 9 per cent and Michael Gove was last with 6 per cent.

Stephen Barclay has written to the European Union's chief Brexit negotiator, Michel Barnier, asking him to fully consider proposals to ring-fence citizens' rights regardless of how the UK leaves the EU.

The Brexit secretary said joint efforts should remain focused on ensuring an agreement is reached to allow the UK to leave with a deal, but suggested officials "continue to work on how we best protect citizens' rights in all scenarios".

He wrote: "I believe we collectively have an opportunity to address these concerns and that we should make sustained efforts to do so, including by fully considering these proposals and the technical issues raised in your letter.

"I note that there is gathering support from Parliamentarians in the European Parliament and other Member States for so doing."

It comes after an amendment tabled by Tory backbencher Alberto Costa to guarantee citizens' rights was passed without opposition in the Commons in March, despite Theresa May warning the EU would not be able to strike a deal of this kind.

Here is Andrew Woodcock's analysis of the first debate and hustings of the Conservative leadership campaign, as the candidates prepare to take part in a second live TV debate:

Philip Hammond has refused to rule out resigning as chancellor over Theresa May's attempt to spend billions on her "legacy", Rob Merrick writes:

Downing Street said Theresa May's future spending plans did not come up in Cabinet, but said the chancellor offered his views "across a wide range of topics".

The prime minister's official spokesman said: "You have seen significant announcements made by the prime minister with full Cabinet support in recent days, including one today in relation to protecting consumer rights, one yesterday in relation to mental health and the commitment on climate change."

Asked if Ms May would like the chancellor not to resign, the spokesman said: "It's been quite hard keeping up with all the anonymous quotes from friends of the chancellor in recent days.

"But I would simply say he was in Cabinet this morning and offering his views across a wide range of topics."

When asked about a poll which showed Tory members would be prepared to sacrifice the union, destroy their party or suffer economic damages to get the UK out of the EU, Theresa May's official spokesman said: "Right from her very first day in office and throughout the Brexit negotiations, the prime minister has placed great importance upon securing the Union.

"It is hugely important to her and I think you have seen throughout her commitment to trying to protect the integrity of the Union."

Michael Gove and Jeremy Hunt have traded barbs in interviews with the Evening Standard, with the environment secretary saying his rival has treated Brexit like an "unexploded bomb" and the foreign secretary claiming he has the "experience" and "relationship of trust" to negotiate a new deal with the EU.

Responding to an article in The Guardian headlined "Tory rivals turn on Rory Stewart as campaign gathers momentum", the leadership hopeful has tweeted: "I seem to be doing something right."

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