Jeremy Corbyn has signalled Labour is unlikely to back any Brexit deal struck by Boris Johnson, even if there was a confirmatory referendum.

On Saturday, shadow Brexit secretary Sir Keir Starmer said that if the Prime Minister returned from Brussels with an agreement Labour would demand it was put to the country in a confirmatory vote.

However, questioned on Sky News’s Sophy Ridge on Sunday programme, Mr Corbyn showed little enthusiasm for the idea.

Shadow Brexit secretary Sir Keir Starmer has said Labour would call for a referendum on any deal (Gareth Fuller/PA)

“I think many in Parliament, not necessarily Labour MPs, others, might be more inclined to support it (if there was a referendum) even if they don’t really agree with the deal. I would caution them on this,” he said.

Mr Corbyn said there was now a “strong possibility” that there would be a general election before Christmas.

He said that it was “ludicrous” for the Government to be holding a Queen’s Speech on Monday when it was more than 40 votes short of a Commons majority.

“It obviously depends on what happens this week, but we have a Government that is now in minus 40, it hasn’t yet won a vote in Parliament,” he said.

“Having a Queen’s Speech and a State Opening of Parliament tomorrow is ludicrous. What we have got in effect is a party political broadcast from the steps of the throne.”

Mr Corbyn insisted that if the Government collapsed before an election, he should have the first chance of forming a new government rather than a more consensual figure who could command cross-party support.

“I am the Leader of the Opposition. All the British parliamentary precedents going back as long as you care to look are that the first option is that the Leader of the Opposition is invited to form an administration in order to deal with the specific points to make sure that we get a deal with the European Union,” he said.

“We will form an administration if this Government collapses with the purpose of a deal and take this country forward to decide its own future through an election and the people get to decide their future in a referendum.”

Shadow chancellor John McDonnell has said he expects Mr Corbyn to stand down if Labour loses the next general election (Victoria/PA)

Mr Corbyn refused to say if he would stand down as party leader if Labour lost the next general election.

Shadow chancellor John McDonnell has said he expected that they would both step down and that there would be a leadership election if Labour was defeated.

However, Mr Corbyn said: “We are not expecting to lose the next election. It is a hypothetical question. It is up to the members of our party to decide who the leader is.

“John gave an answer to an interview that he undertook. My answer is this: I am leading this party to go into an election.”