BORIS Johnson’s government always knew they’d “ditch bits” of the Brexit deal they didn’t like, the Prime Minister’s former chief adviser has claimed.

In a series of tweets last night, Dominic Cummings told followers that while he believed the Government should generally stick to the deals it agrees, it should also “sometimes break them”.

The Vote Leave chief, who was instrumental in pushing Johnson’s “Get Brexit Done” message, left Number 10 last year following a power struggle.

While he has been highly critical of his former boss in the following months, he has continued to defend Brexit and its implementation.

It comes as the EU is set to outline its range of proposals aimed at resolving the stand-off over the Northern Ireland Protocol.

European Commission vice president Maros Sefcovic has promised the measures will be “very far-reaching” and address issues over the movement of agri-food goods and medicines across the Irish Sea.

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While the measures may potentially go some way to reducing everyday friction on trade between Great Britain and Northern Ireland, they are unlikely to satisfy a UK Government demand over the role of the European Court of Justice (ECJ).

Yesterday, UK Brexit negotiator Lord Frost made clear the removal of the ECJ’s oversight function in relation to the protocol was a red line for the Government.

Under the terms of the deal struck by the UK and EU in 2019, the ECJ would be the final arbitrator in any future trade dispute between the two parties on the operation of the protocol.

The UK now wants to remove that provision and replace it with an independent arbitration process. Sefcovic has insisted that the EU will not move on the issue.

Amid the ongoing row, with questions over why the UK Government agreed to and promoted a deal they now have these issues with, Cummings took to Twitter.

Reflecting on the 2019 General Election, he wrote: “We wriggled [through] with best option we could and intended to get the trolley [Johnson] to ditch bits we didn’t like after whacking Corbyn.

“For all the cant about international law, a) states break it every week, b) the idea it's the epitome of morality is low grade student politics pushed by lawyers/officials to constrain politics they oppose.”

He went on: “Should we generally stick to deals? Of course. Sometimes break them? Of course. Just like the EU, US, China and every other state does.”

Challenged over whether this meant Johnson was “lying” about Brexit in 2019, Cummings said that was not the case.

The National:

“He never had a scoobydoo what the deal he signed meant,” the former adviser wrote. “He never understood what leaving customs union meant until 11/20. In 1/20 he was babbling ‘I’d never have signed it if I’d understood it’,” he claimed.

Cummings concluded that getting Brexit done was “10000x more important than lawyers yapping re international law”.

Following the comments, Ireland’s deputy premier warned political leaders not to enter agreements with the UK unless they are confident they will keep their promises.

“I saw those comments; I hope Dominic Cummings is speaking for himself and not for the British Government,” Tanaiste Leo Varadkar told RTE Morning Ireland.

“But those comments are very alarming because that would indicate that this is a Government, an administration, that acted in bad faith and that message needs to be heard around the world.

“If the British Government doesn’t honour its agreements, it doesn’t adhere to treaties it signs, that must apply to everyone else too.

The National:

“At the moment they’re going around the world, they’re trying to negotiate new trade agreements… Surely the message must go out to all countries around the world that this is a British Government that doesn’t necessarily keep its word and doesn’t necessarily honour the agreements it makes.

“And you shouldn’t make any agreements with them until such time as you’re confident that they keep their promises, and honour things, for example, like the protocol.”

Philippa Whitford, the SNP's Europe spokesperson, said the remarks demonstrate the Government's "complete disregard" for its Brexit deal and international law.

"The Tories were happy to claim the Withdrawal Agreement as a great success at the time but now want to go back on the key principles they signed to protect the Northern Ireland Peace process," she told The National.

"Rather than meaningfully engaging with our EU neighbours to address the challenges facing the UK as a result of Brexit, the Tory government is instead adopting an increasingly insular and hostile approach.

"The Brexit mess is entirely of the Tory government's making - with businesses and households being forced to pay a heavy price.

"It's clear that Scotland is vulnerable under Westminster control. The only way to protect our interests and escape the long-term damage of Tory Brexit, is to become an independent country with the power to make our own decisions."

Meanwhile, Labour’s business, energy and industrial strategy secretary Ed Miliband has criticised the Government’s Brexit deal as being “half-baked”, drawing on the Prime Minister’s slogan that it was “oven-ready” at the time of signing.

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The MP for Doncaster North told Sky News: “I hope there’s compromise on both sides. I think people will be scratching their heads because this was an agreement signed by Boris Johnson, he said it was a fantastic triumph, it was all going to be fine – and now they want to rip up their own protocol.

“I actually think there’s a case for a wider EU-UK veterinary agreement because that would then make the goods situation in Northern Ireland much easier, it would agree common standards.”

Asked if he thinks the deal was “oven-ready”, he said: “It was half-baked.”