Theresa May’s Chequers plan is a “very serious breach of trust” with the British public, a Tory grandee has claimed.

Leading Brexiteer Sir Bill Cash told MPs the Prime Minister’s blueprint for Brexit succeeded only in “undermining” the referendum result.

The European Scrutiny Committee chairman made the comments in the Commons after former Brexit minister Steve Baker had warned the plan could cause a “catastrophic split” in the Conservative Party.

Mr Baker, a leading figure in the pro-Brexit Tory European Research Group, told the Press Association he was “gravely concerned” about a potential schism in Tory ranks if the Prime Minister did not change direction.

Sir Bill echoed the warning in the Commons, telling ministers: “It was Chequers that did it, up to Chequers I was 100% behind the Government.

“This is an unacceptable arrangement”, he said. “I regard this as a very, very serious breach of trust.”

He added: “I think a lot of people outside, what we call the punters, the real people of this country, know and understand it.

“We decided on that 26 June 2016 to leave the European Union, we did not agree that we were going to come back in some form of legal reentry to satisfy the whims of the EU and particularity those who dominate it most, namely Germany itself.”

EU Membership conference – London
Sir Bill Cash was critical of the plans (PA)

Conservative former cabinet minister John Redwood also raised concerns over the Chequers proposals, as MPs debated legislating for the withdrawal agreement.

Mr Redwood said the Government needed to make it “absolutely crystal clear that there’s no £39 billion unless something really impressive is available”.

Mr Redwood added: “When I go shopping, I don’t go into the shop and put £39 down by the till and say very politely ‘Oh, by the way, I’ve got £39 there for you, I thought you might like it, is there something you’ve got I might like so I don’t go out the loser from this shop?’.”

He said this is what the Government appeared to have done, noting: “I am afraid when I look at what the EU has in their shop, I don’t really see anything I’d pay £39 billion for.”

Mr Redwood said Canada “did not pay anything” for its free trade deal although SNP MP Philippa Whitford (Central Ayrshire) insisted the cash was the equivalent of ensuring you “pay your tab” before leaving.

In light of the comments from the ERG members Labour MP Stephen Doughty (Cardiff South and Penarth) questioned how any Brexit deal would proceed, saying: “Isn’t the reality the Prime Minister’s Chequers deal is dead, we’re heading for a disastrous no deal and that’s exactly why we need a people’s vote on the deal?”

Brexit Minister Suella Braverman replied: “I disagree with you on your suggestion for a second referendum – that would be a complete betrayal of the voters because we had that exercise and that was two years ago.

“I’m optimistic we’re going to strike a mutually beneficial free trade agreement with the EU which honours the result of the referendum, retains the territorial integrity of our country and which enables a smooth withdrawal from the EU.”

Shadow Brexit minister Matthew Pennycook later demanded clarity over the final deal this autumn, instead of a “blind Brexit”.

He said: “There’s every incentive, practically and politically, for the government to come back with a withdrawal agreement that contains political agreement that’s highly ambiguous.

“To do so would be unacceptable. A vague political declaration would not be a solution to the problems we’re grappling with, it would be tantamount to avoiding the problem altogether and would leave us in a far weaker position.”

Mrs Braverman claimed the withdrawal agreement was “part of the final deal package” that would be “put to parliament for the meaningful vote”.

Arch-Brexiteer Jacob Rees-Mogg, chairman of the European Research Group behind the “chuck Chequers” campaign, said the current deal left the UK like “Gulliver tied down by Lilliputians”.

“It is absolutely the vassal state,” he said. “This great nation state tied down by the petty bureaucrats running all over us, tying us down with ropes, so we have to do whatever the EU says we have to do for an implementation period.

“Our laws will be a made by a foreign body in which we have no say, no vote and no association.

“Countries have become colonies before but normally it is with a little bit of encouragement, at the end of a bayonet or a spear or some such – it’s most unusual to volunteer to allow a foreign organisation to make your laws. Unprecedented.”

Former Europe minister Chris Bryant later called on the Government to seek to extend Article 50.

The Labour MP said: “They should certainly be getting on with doing that because Article 50 was crazy to have started it, but it would be even crazier to stick with that date if you cannot produce proper legislation so there is legal certainty in the United Kingdom.

Mr Bryant also spoke of his “anger” at David Cameron and what he described as the ex-prime minister’s “appeasement of the far right”.

The Rhondda MP said: “He appeased the far right in this country, of course lots of people are always tempted by appeasement of the far right – they make a lot of noise.

“The message that we’ve known for centuries is surely if you try to appease somebody all they do is they consume you, and that’s exactly what happened to David Cameron and that’s why we had the referendum in the first place.”