MPs are set to vote once again on Tuesday whether to back the government’s plans to override parts of its Brexit agreement with the EU.
Amid concerns that the move would break international law, ministers have agreed to give Parliament a say before ever using the powers they would be granted by the Internal Market Bill.
The legislation is expected to pass before going to the House of Lords.
But former Prime Minister Theresa May has said she “cannot support” it.
It is not known whether Mrs May – one of several Conservative MPs who have raised concerns over possibly undoing parts of a treaty signed with the EU – will actually vote against her successor Boris Johnson’s government.
The parliamentary debate comes as the EU and the UK begin a ninth – and final – scheduled round of talks aimed at securing a trade deal.
The post-Brexit transition period – in which the UK has kept to EU trading rules and remained inside its customs union and single market – runs out at the end of the year.
If the sides fail to reach a deal, the UK would trade with the EU after that on World Trade Organisation rules.
This would mean tariffs on most goods which UK businesses send to the EU, while the UK could also apply tariffs to EU goods.
The Internal Market Bill is designed to enable goods and services to flow freely across England, Scotland, Wales and Northern Ireland after 1 January.
It gives the government the power to change aspects of the EU withdrawal agreement, a legally binding deal governing the terms of Brexit earlier this year.
What is the Internal Market Bill?
The bill sets out rules for the operation of the UK internal market – trade between England, Scotland, Wales and Northern Ireland – after the end of the Brexit transition period in January.
- No new checks on goods moving from Northern Ireland to the rest of Great Britain
- Giving UK ministers powers to modify or “disapply” rules relating to the movement of goods that will come into force from 1 January if the UK and EU are unable to reach an alternative agreement through a trade deal
- Powers to override previously agreed obligations on state aid – government support for businesses
Ministers say the bill’s provisions would provide a “safety net” in case the EU interprets the agreement, in particular the section on Northern Ireland, in an “extreme and unreasonable” way. The section – known as the protocol – is designed to avoid a hard border on the island of Ireland.
Speaking in Tuesday’s Commons debate, Business Minister Paul Scully said it was important to “ensure that trade remains unhindered in the United Kingdom in the future”.
Labour, the SNP and the Liberal Democrats oppose the bill, while the EU has asked the UK government to remove “contentious parts” of it by Wednesday.
As well as Mrs May, the other four living former prime ministers – Sir John Major, Tony Blair, Gordon Brown and David Cameron – have spoken out against it.
But the Democratic Unionist Party is supporting the government, which already has a Commons majority of almost 80.
MPs will debate amendments put forward to the legislation before taking a final – third reading – vote on it. If it is passed, it will go to the House of Lords for further scrutiny.