Rishi Sunak’s Brexit deal does not restore Northern Ireland’s place in the union, a group of eurosceptic Tory MPs has warned, ahead of a crunch vote on Wednesday.

The European Research Group (ERG) criticised the Windsor agreement struck with the EU, saying that it falls well short of delivering what the Prime Minister promised.

But in a boost to No 10 its chairman, Mark Francois, suggested that the 30-strong grouping may not take a unanimous decision to oppose the pact in the Commons.

Downing Street has insisted that it will not be making any changes to the deal after the DUP said that it will vote against its implementation on Wednesday.

The ERG had tasked a ‘Star Chamber’ of lawyers and senior MPs with going through the Windsor Framework to check whether it matched up to Government rhetoric.

Mr Francois said: “The Star Chamber’s principal findings are that EU law will still be supreme in Northern Ireland, the rights of its people under the 1800 Act of Union are not restored, the ‘green lane’ is not really a ‘green lane’ at all, the Stormont Brake is practically useless, and the framework itself has no exit other than through a highly complex legal process.”

His remarks came after Sammy Wilson, the DUP’s chief whip in Westminster, vowed his party will continue to “fight” for improvements to the deal.

“We got the negotiation, but we didn't get the outcome so we have to continue the fight, and we will continue the fight,” he said.

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