Theresa May and David Davis set for Brexit clash over Irish border plan

Theresa May and David Davis are gearing up for a showdown over a “backstop” plan to protect Ireland's open border after Brexit.

Ministers were preparing to publish their so called “temporary customs arrangement” today but the big reveal is likely to be pushed back to the end of the week, according to reports.

The document contains a proposal to temporarily align the UK with the EU customs union when the Brexit transition ends in December 2020 if no new arrangement has been agreed.

The plan is an emergency measure to keep the border between Ireland and Northern Ireland open - but the Brexit Secretary has raised concerns that it contains no specified end date.

Tensions are set to be aired at a meeting of the Brexit war cabinet this afternoon.

Rumours have been swirling that Davis could even quit over the issue - although yesterday he said his position was “a question for the Prime Minister, to be honest”.

Speaking after a speech in London, he said: "The detail of this is being discussed at the moment.

“It's been through one Cabinet committee, it's going to another one and it will be improper of me to pre-empt the negotiation there but I suspect it will be fairly decisive tomorrow."

Downing Street has insisted it does not expect the backstop plan to be needed - but it is yet to reveal its proposals for future customs arrangements with the bloc.

Meanwhile, the Times reports that other pro-Brexit Cabinet ministers felt they were being kept in the dark as they were granted access to the four-page document days after it was shown to pro-EU colleagues.

Davis is also said to be angry that his landmark Brexit white paper - previously promised before the end of the month - has been put on the backburner.