Video report by ITV News Political Correspondent Romilly Weeks
– What exactly is being proposed?
The government is planning to implement legislation on state aid and Northern Ireland customs - should Brexit talks fail - a move which would go against what was signed in the Withdrawal Agreement in October last year.
The move would get rid of the requirement for new customs arrangements in Northern Ireland.
The Northern Ireland protocol aspect of the Withdrawal Agreement would be replaced with domestic legislation called the Internal Market Bill.
If implemented, the Bill would end the legal legitimacy of the Withdrawal Agreement in areas such as NI customs and state aid and financial assistance.
It will ensure goods from Northern Ireland continue to have unfettered access to the UK market while making clear EU state aid rules - which will continue to apply in NI - will not apply in the rest of the UK.
ITV News Correspondent James Mates has more:
At present Northern Ireland is supposed to adhere to some EU regulations after the Brexit transition period ends on December 31 in a bid to stop a “hard border” on the island of Ireland.
In addition, the Finance Bill would give ministers the power to designate which goods going from Great Britain to Northern Ireland are considered "at risk" of entering the EU single market and are therefore liable to EU tariffs.
The prime minister's spokesman said the legislative changes were a necessary "safety net" in the event that they were unable to come to an agreement.
– Why is the UK taking this stance?
Despite the Withdrawal Agreement being reached in October 2019, both sides recognised, when it was signed, that the deal had a "few loose ends".The Joint Committee was set up so both sides could debate the remaining areas of contention - state aid and Northern Ireland customs - and come up with solutions.
The government now says with talks at such a late stage, that it is necessary to prepare its own legislation to "give legal clarity" if there "remains a few issues at the end of [talks]".
The PM's spokesman said: "So we are taking limited and reasonable steps to clarify specific elements of the Northern Ireland protocol in domestic law to remove any ambiguity and to ensure the Government is always able to deliver on its commitments to the people of Northern Ireland."
A UK official added: "If we don't take these steps we face the prospect of legal confusion at the end of the year and potentially extremely damaging defaults, including tariffs on goods moving from GB to Northern Ireland."
Negotiations by the Joint Committee take place between Chancellor of the Duchy of Lancaster Michael Gove, and EU Commission Vice President, Maroš Šefčovič.
Negotiations on a trade deal take place between UK chief negotiator David Frost and his EU counterpart Michel Barnier.
– Hasn’t Brexit already happened?
The UK has formally left the EU, but adheres to the bloc’s trade rules and regulations until the end of the year.
A trade agreement was intended to be worked out by then, but the process has been slow and acrimonious, particularly regarding issues such as fishing rights.
Both sides have said a deal would need to be done by mid-October in order for it to be ratified in time.
– How has the EU reacted to the Government’s move?
Ursula von der Leyen, President of the EU Commission said the Withdrawal Agreement is a "prerequisite for any future partnership" and suggested there will be no trade deal if the UK does not stick to its side of it.
In response to reports that some aspects of the agreement could be ignored, Ms von der Leyen tweeted: "I trust the British government to implement the Withdrawal Agreement, an obligation under international law & prerequisite for any future partnership.
"Protocol on Ireland/Northern Ireland is essential to protect peace and stability on the island & integrity of the single market."
Irish Foreign Minister Simon Coveney has branded the UK course of action “unwise”.
And EU chief negotiator Michel Barnier said he will be seeking clarification of the UK’s plans.
– How is the UK Government presenting the situation?
It is playing it down.
Environment Secretary George Eustice insisted the measures are intended to tie up “loose ends” and not meant to rip up the agreement with the EU.
He told the BBC: “What we are talking about here is what type of administrative customs processes you might have for goods that might be at risk of entering the EU single market – going from GB to Northern Ireland. These are important but minor technical details.”
– What does the opposition say?
Labour has accused Prime Minister Boris Johnson of misleading people.
Shadow health secretary Jonathan Ashworth told the BBC: “Boris Johnson, I thought, told us he had an oven-ready deal. And, he fought a general election telling us he had an oven-ready deal; now suggests that he was misleading people in that general election.”
– What happens next?
The eight rounds of talks between Britain and the EU begins on Tuesday, and the Government is expected to outline its proposed new legislation on Wednesday.