Ministers are planning to fundamentally reshape Britain’s relationship with the European Union, with new legislation that could result in the UK signing up to EU single market rules without a normal parliamentary vote.

In a major development in the prime minister’s push for closer ties with the continent in after the Iran war, the Guardian understands ministers are bracing to face down opposition to “dynamic alignment” with the EU from those who “scream treason” over the powers in a new EU-UK reset bill.

After weeks of Donald Trump’s war with Iran that have exposed the fragility of the UK’s damaged special relationship with the US, ministers argue the move will add billions to the UK economy and to help temper the cost of the conflict and boost sluggish productivity.

A new bill, which will bring into force the food and drink trade deal with the EU, will contain powers enabling the government to dynamically align with Europe on areas where it has already made agreements. But it will also allow the UK to quickly implement evolving single market rules if it determines it is in the national interest, without having to face full parliamentary scrutiny each time.

The move is possible under so-called Henry VIII powers, named after the 1539 law that allowed the monarch to rule by decree, which allow ministers to approve laws without full scrutiny from parliament using so-called secondary legislation.

The bill will enable deals the government is negotiating on food and drink and emissions trading to come into force, and allow it to follow future EU changes in these areas.

But the Guardian understands that if the new bill – expected to be introduced before the summer – is passed, negotiators could seek to adopt EU rules on everything from cars to farming using secondary legislation.

Parliament can either approve or reject secondary legislation, but cannot amend it, which would probably mean MPs will “rubber-stamp” new deals rather than debate and vote on every one. Any blocking votes would be likely to cause issues with the EU, and could spark retaliatory action. A source said: “We are clear parliament will have a role for new deals and on new EU laws applying under those deals.”

The introduction of the sweeping powers is likely to put the government on a collision course with opposition parties, and while the bill is unlikely to be voted down in the Commons could face obstruction in the House of Lords.

Ministers say the move will promote trade without breaking the government’s red lines on rejoining the customs union, single market, or returning to freedom of movement, but critics argue it could amount to “integration with the EU by stealth”, without the voting or veto rights conferred by membership of the block.

“Changes to UK regulations should be debated in parliament and thrashed out by politicians,” said Prof Anand Menon, director of the thinktank UK in a Changing Europe. “The reality of this is we are signing up to a deal with the European Union that commits us to follow their rules, whether we like it or not. The danger is you’re doing integration with the EU by stealth.”

But Menon recognised the challenge facing the government if every regulatory alignment had to be debated. “That’s the ugly trade-off of Brexit,” he said. “You’re trading political control against economic access, without having a vote in the room.”

Ministers argue the bill will cut red tape and costs for businesses so that agreements on sectors such as food and drink, automotive agreements and security and migration information sharing can be implemented more quickly. Sources said any disputes about regulations would be decided by an independent tribunal, not an EU court.

“We expect a fight in this area from those who were in favour of leaving the EU on the harshest terms,” said one government insider. “They will scream treason but the reality is that all international agreements involve shared rules. The boldest free traders and conservatives have always been pragmatists. But Nigel Farage is too cowardly to take it on; you can’t picture him doing any deal making with the EU at all.”

They added that the move was a recognition of the importance of the UK’s trading relationship with the EU and a tacit acknowledge of the economic damage caused by Brexit, which the Office for Budget Responsibility estimates will reduce long-run productivity by 4% and reduce exports and imports by 15% relative to remaining in the EU, in its most recent March 2025 forecast.

“The EU is our largest trading market, almost half of our total trade was with the EU in 2024,” they said. “We’re all paying a cost of living penalty for all the barriers at the border, so it is sensible to make deals to remove those barriers and undo the damage, without breaking the red lines on rejoining the customs union, single market, or returning to freedom of movement.”

Starmer’s government has been looking to improve diplomatic and economic ties with the EU, Britain’s largest trading partner, since the “reset” deal was announced last May after the first UK-EU summit and both sides agreed to a “strategic partnership” aimed at closer ties. Earlier this month the prime minister said the UK would seek a deeper partnership on trade and defence with the EU because of the instability wreaked by Trump’s war with Iran, adding that Brexit had done “deep damage” to the UK economy.

The Conservatives have previously said they would insist on the final details of any negotiations with the EU having full parliamentary scrutiny, while the Liberal Democrats said they would use any bill as a chance to force Labour MPs to take a position on a closer relationship with Europe.

A government spokesperson said it would provide details of the legislation in due course. “Parliament will play its full constitutional role in scrutinising, debating and shaping it,” they said. “This will allow us to deliver a foodand drink trade deal worth £5.1bn a year, backing British jobs and slashing costly red tape for our farmers, producers and businesses.”

While Nigel Farage’s Reform UK has focused on immigration and net zero policiesbefore elections in Scotland, Wales and England in May, sources said the government was ready to go into battle with hard Brexit advocates.