Northern Ireland is to be handed more extra powers than Scotland or Wales under the UK Government's plans for dealing with Brexit.
Measures that were previously regulated by the European Union will return to the UK at the end of the year when the transition period expires.
Responsibilities in 160 policy areas - including animal welfare, public procurement rules and environmental regulations - will now go to one or more of the devolved administrations.
The way the Government is handling the return of powers from Brussels has already provoked a row with Nicola Sturgeon's administration in Scotland after it was revealed that Whitehall will assume control of the state aid regime.
The proposed changes - set out in a white paper being published today for consultation - will see Northern Ireland receive responsibility in 157 of the 160 areas, Scotland in 111 and Wales in 70.
As this could lead to different regulatory regimes in the UK the Government has drawn up plans for the "internal market" to ensure seamless trade between the home nations. At the heart of the plans are the principles of mutual recognition - so regulations in one part of the UK are recognised in all the other nations - and non-discrimination, providing a "level playing field" for companies across the UK.
Officials said that without these actions a Welsh lamb producer could end up unable to sell their meat in Scotland, or Scotch Whisky producers could lose access to supply from English barley farmers. Northern Ireland Secretary Brandon Lewis said: "This plan is vital to protect jobs and livelihoods across all four nations of the UK. Northern Ireland exports more to the rest of the UK than to all of the EU combined - nearly 60% of Northern Ireland's total external trade is with Scotland, Wales and England.
"We will be enshrining in law the UK Government's guarantee that Northern Ireland businesses will benefit from unfettered access to the whole UK market. And we will implement the Northern Ireland Protocol in a way which safeguards the effective working of the UK's internal market.
"Making sure that seamless domestic trade can continue will support our economic recovery, provide certainty for businesses and create more opportunities for investment across Northern Ireland."