The British government has published its plans for "backstop" customs arrangement with the EU after Brexit, which includes an "expected" cut off date of December 2021.
Prime minister Theresa May had a hastily-arranged meeting with her ministers earlier on Thursday after the plans attracted serious opposition from a leading member of the cabinet, Brexit secretary David Davis.
Mrs May had proposed to temporarily tie the UK into existing EU customs rules if a permanent deal is not struck before the UK leaves the bloc.
Mr Davis, the face of the British Brexit negotiating team in Brussels, and other leading Brexiteers were said to be unhappy that the arrangement had allowed for the possibility that the UK could remain tied to EU rules for an indefinite period after March 2019.
However, the document published on Thursday afternoon after Mrs May had her emergency meeting with Mr Davis and his allies, said that it expected a future deal to be in place by the end of 2021.
Sources close to Mr Davis claimed the addition of the "expected" cut off date as a victory for the Brexit secretary.
Reports in the British press said he had been prepared to resign over the issue. Such a resignation would have been disastrous for Mrs May, whose fragile government is without a parliamentary majority.
Former Brexit minister David Jones told BBC Radio 4’s Today show that continuing with the negotiations without Mr Davis would be “deeply upsetting and deeply dangerous for the country and David Davis needs to stay where he is”.
The customs union, which allows trade without tariffs for all countries in the EU, has been a major sticking point for the UK government in its Brexit negotiations.
Mrs May has said the UK will leave the customs union after Brexit but the government has struggled to come up with an alternative arrangement, which is acceptable to the EU to avoid the need for border checks between Northern Ireland and the Republic of Ireland.
The EU proposed keeping Northern Ireland in the customs union but this was rejected by the government as well as Northern Irish party the DUP, which is holding together Mrs May’s minority government.
The latest so-called “backstop” option would see the whole of the UK aligned to the EU’s customs union temporarily after the 21-month transition period ends in December 2020. The plan, which would see the UK setting its tariffs at the same rates as the EU, would allow the government to sign and implement trade deals.
Downing Street said the backstop plan was unlikely to be needed but this has not allayed the concerns of pro-Brexit Conservative politicians, who wanted a clear end date for the proposal.