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Theresa May will meet with senior ministers later in a try and resolve tensions over the federal government's Brexit "backstop" plan.
In the proposal the UK would match EU tariffs briefly with a view to keep away from an arduous Irish border post-Brexit.
Number 10 had been anticipated to publish the "temporary customs arrangement" on Thursday, however confronted resistance from Brexit Secretary David Davis.
Its publication may now be delayed till the top of the week.
The proposal will define what would occur ought to no everlasting answer be agreed with the EU earlier than the UK's 2019 exitnevertheless it may not specify a finish date.
BBC political editor Laura Kuenssberg stated Downing Street believed it had sufficient help from senior ministers to publish the proposal.
"But what they hadn't quite bargained for was the level of resistance from the man who is meant to be in charge of this process (Mr Davis)," who needs a time restrict added to the backstop, she added.
Mr Davis advised a press convention on Wednesday that he "expected" there to be a time restrict within the signed-off model of the plan.
Speaking in London, he stated the small print had but to be authorised and that he believed Thursday's assembly of the cupboard's Brexit sub-committee could be "decisive".
Number 10 says it doesn't imagine the contingency plan will ever come into impact as a result of a customs associationseen as very important to stopping an arduous border between Northern Ireland and the Republic of Irelandcould be agreed as a part of the general withdrawal deal.
But proposals would come with a time restrict, Downing Street has stated.
No 10 have ready a proposal for a "Temporary Customs Arrangement", the place the UK would retain shut ties to the EU for an indeterminate interval after the top of the transition intervalprevious 2020in case none of their hoped for customs fixes come to go.
They believed they'd the help of senior ministers to publish it on Thursday, even with out express and detailed discussions of the written paper itself within the internal Brexit cupboard, not to mention the complete gathering of senior ministers.
It grew to become clear, nonetheless, and slightly surprisingly to the surface observer, that the person in authorities who is supposed to be in control of the Brexit course of was not fully on-board.
So the brakes have been slammed on publishing the paper till conferences and discussions between senior ministers on Thursday.
Sources in Brussels have advised BBC Europe editor Katya Adler that Mr Davis will go to Brussels on Monday after requesting an "informal" assembly along with his EU counterpart, Michael Barnier.
The UK has stated it can depart the EU's customs union however has but to agree on what's going to change it.
The UK has stated that the EU's proposed choicepreserving Northern Ireland within the customs unionwould successfully create a border between Northern Ireland and the remainder of the UK and was not acceptable.
Instead, the UK is proposing a "backstop" choice which is able to see the UK briefly aligned with the EU's customs union after December 2020when the 21-month post-Brexit transition interval ends.
The plan, which Theresa May has stated would solely apply in a "limited set of circumstances", would see the UK match EU tariffs with a view to keep away from border checks and permit it to signal and implement its personal commerce offers.
The BBC understands the plan circulated amongst some ministers on Wednesday morning refers explicitly to the entire of the UK slightly than simply to Northern Ireland.
Pressed on the problem at Prime Minister's Questions, Theresa May insisted the UK was on observe to go away the EU in March 2019 and that the transition interval would final not than 31 December 2020.