Jeremy Corbyn has urged his MPs not to “engage” with the Government over a Brexit deal after at least three prominent backbenchers took up an offer of talks with ministers.

The Labour leader sent a letter to members of the parliamentary party after Hilary Benn, Yvette Cooper and John Mann all visited the Cabinet Office in Whitehall on Thursday.

Their visits came just hours after Mr Corbyn had used a speech in Hastings to reiterate his demand that a no-deal Brexit must be ruled out before he would take up Theresa May’s offer of talks.

In front of around 200 activists in Hastings he blasted the offer of cross-party Brexit talks as a “stunt”, before being applauded by Labour supporters for saying that a second referendum was still an option.

In his letter to MPs Mr Corbyn thanked them for their support in the debates against Mrs May’s Withdrawal Agreement and then in the defeated no confidence vote on Wednesday.

In signing off he said no-deal would be “disastrous” and must be off the table, adding: “I urge colleagues to respect that condition and refrain from engagement with the Government until ‘no deal’ is taken off the table.”

Both Mr Benn, who said he wanted to see if there was an “open mind” behind the offer of talks as he went in, and Ms Cooper echoed Mr Corbyn’s demands on no-deal as they left the Cabinet office later on Thursday afternoon.

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Labour MPs Hilary Benn and Yvette Cooper in Whitehall, London outside the Cabinet Office, after the Prime Minister announced that she would invite party leaders in the Commons and other MPs in for discussion to get a Parliamentary consensus on the way forward over Brexit (Stefan Rousseau/PA)

The chairman of the Exiting the EU Committee told reporters: “The Government knows as well as anybody else the damage that would be caused by no deal so why continue to pretend that they might be prepared to take the UK out of the EU on March 29 without an agreement?

“The essential first step is for the Government to say ‘we will not do that because it’s in nobody’s interest for that to happen’.”

Ms Cooper, the Home Affairs Committee chairwoman, added: “I think the damage no deal would do would be so huge to our manufacturing industry, but also our policing and security, and that’s why we had a vote in Parliament to say the Government should not be going ahead with no deal.”

The opposition leader had earlier told an audience in East Sussex that the Prime Minister had made no “serious attempt to engage with the new reality that is needed” to get a Withdrawal Agreement through Parliament.

In a direct message to Mrs May, Mr Corbyn said: “Take no-deal off the table now please, Prime Minister.”

He reiterated Labour’s preference for a general election and a Brexit deal on its terms, including a permanent customs union, close links to the single market and protections for workers and the environment.

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Jeremy Corbyn was applauded when he said all options, including a second referendum, remained open (Gareth Fuller/PA)

To clapping from the floor, he added: “If the Government remains intransigent, if support for Labour’s alternative is blocked for party advantage and the country is facing the potential disaster of no-deal, our duty will then be to look at other options which we set out in our confidence motion, including that of a public vote.”

However, taking questions after his speech at the venue on Hastings’ seafront, he left open the question of which side Labour would campaign on in a public vote.

“If a second referendum should take place, then obviously the party will decide what role we will play in that and what our view would be,” he said.

“But I can’t really go along with the idea it should simply be a re-run of what happened in 2016. There has to be a discussion about the options that we put forward and we’ve put forward the three options that I’ve outlined.”

Mr Corbyn said he had written to the Prime Minister on Thursday setting out his position.

He confirmed that Labour will table amendments to Monday’s motion, putting forward its preferred solution of a customs union with a voice for the UK in future EU trade deals, a close single market relationship and protections for rights.

He held open the possibility of an extension of the Article 50 negotiation period, saying: “Quite clearly, if no agreement has been reached within the time it could be implemented by the end of March, the issue of extending the exit date, extending Article 50, does come into play.

“Indications are that that may well be the case.”

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Labour MP John Mann leaving the Cabinet Office (Victoria Jones/PA)

Mrs May later replied to his letter and questioned his decision to ask MPs not to take part in talks.

She wrote: “You have always believed in the importance of dialogue in politics.

“Do you really believe that, as well as declining to meet for talks yourself, it is right to ask your MPs not to seek a solution with the Government?”

Mr Mann, a Leave-supporting Labour MP and long-term Corbyn critic, came out of the Cabinet Office an hour after the leader’s speech.

Another backbench Labour critic, the east London MP Mike Gapes, criticised the party leader’s attitude to talks, tweeting: “Apparently Corbyn is prepared to hold talks with Hamas, Hezbollah, Assad and Iran without preconditions. But not with the UK Prime Minister. Why?”