Keir Starmer set to unveil ‘Brexit Betrayal Bill’ to hand power to EU without any say from British voters

No10 hopes the deal will underpin the UK’s relationship with the EU after Brussels struck an accord on food standards with Labour last year.

However, pursuing “dynamic alignment” would mean the UK is bound by EU rules on any issues included in negotiations.

Brexiteers warn such a concession would mark the first loss of UK sovereignty on standards since Britain’s departure from the EU.

Despite Britain voting to leave the EU in 2016, such an arrangement would also remove any process of parliamentary or public consent on individual areas subject to “dynamic alignment”.

Shadow Foreign Secretary Dame Priti Patel said Labour’s “Brexit betrayal” was “becoming clearer by the day” and accused Sir Keir of “trying to undo the democratic decision of the British people”.

However, a Labour source said: “The bill will give us the powers to share rules with the EU. All international agreements involve shared rules. That’s their very nature.

“We’re confident in making the case for specific trade-offs, where it has clear benefits for businesses and consumers.

“Priti Patel has a short memory – it wasn’t long ago her boss was making similar arguments, when she U-turned on the Brexit bonfire of EU regulation in the name of pragmatism and what works in the real world.”

Ministers believe closer alignment with the EU will turbocharge economic growth.

Sir Keir soft-launched the policy over the weekend, although he stopped short of buckling to demands to rejoin the customs union.

Speaking to the BBC, Sir Keir said: “I think we should get closer, and if it’s in our national interest to have even closer alignment with the single market, then we should consider that, we should go that far.”

He added: "We’re already aligning on energy, reconnecting to energy in Europe on emissions, but I think the single market further alignment, as I say, if it’s in our interest to do so, we should take that step."

Despite admitting he had “argued for a customs union for many years”, the Prime Minister now thinks “a lot of water has now gone under the bridge” and it would no longer be the right approach.

He also warned a customs union with the EU risks torpedoing the UK's new trade deals, including the accord negotiated with India.

However, Reform UK leader Nigel Farage previously argued such a pivot is "breaking faith with his manifesto pledges on the EU".

It is not the first time in recent weeks the Prime Minister has been accused of "betraying" Brexit.

The Government last month announced it would rejoin the EU's Erasmus student exchange scheme, costing around £570million for one year of membership.

EU relations minister Nick Thomas-Symonds said the breakthrough "is a huge win for our young people", who will be able to study, train or gain work experience under the EU scheme from January 2027.

The UK left the scheme under Boris Johnson, who argued it did not offer value for money.

Downing Street insisted it is "a good deal", while declining to deny reports the UK had pushed for a larger reduction in fees, saying only that negotiators, "as with every area of international engagement, pushed for the best deal for the British people".

Dame Patel accused ministers of "throwing away billions of pounds of hard-pressed taxpayers’ money on rejoining Erasmus" as they "continue to betray Brexit".

Sir Keir will face his first test on January 16 as anti-Brexit Labour MPs look set to vote in favour of a Private Members' Bill demanding the UK rejoins the EU's customs union.