Boris Johnson has admitted a no-deal Brexit would be a “failure” for which he would have to shoulder some of the blame.

The prime minister has committed to taking the UK out of the EU by October 31 even if he can not strike a new agreement with Brussels.

“I want to find a deal. I have looked carefully at no-deal. Yes, we could do it, the UK could certainly get through it, but be in no doubt that outcome would be a failure of statecraft for which we would all be responsible,” Johnson said on Monday morning.

He was speaking at a press conference in Dublin with Irish prime minister Leo Varadkar.

Varadkar warned Johnson there was “no such thing as a clean break” when it came to Brexit.

He said organising trade deals with the US and other governments would be a “Herculean task” for the UK.

Varadkar added he had “not received” any new proposal from the British government that would provide an acceptable alternative to the backstop.

Johnson has said the backstop, which would keep the UK closely tied to EU rules if a trade agreement is not reached, has to be removed from any deal before he will sign up to it.

The prime minister has said he would rather “die in a ditch” than ask the EU to extend Article 50.

MPs have passed legislation that orders the government to request a delay beyond October 31 to prevent a no-deal exit.

According to the The Daily Telegraph, Johnson could “sabotage” the request by asking for an extension while sending another letter rubbishing the request at the same time.

But former Supreme Court justice Lord Sumption told the BBC this morning this would be against the law.

“The Bill, or Act as it’s about to become, says that he’s got to apply for an extension. Not only has he got to send the letter, he’s got to apply for an extension,” he said.

“To send the letter and then try to neutralise it seems to me, plainly, a breach of the Act.