British Prime Minister Theresa May's special Brexit sub-committee has met again without reaching agreement on which of the two proposals on the UK's future customs arrangements that it will back.
The European Union is putting pressure on London to present its preferred option at a meeting of the European Council next month, although the British government insists it will not put a timetable on the process.
Conservative MPs were invited to Downing Street yesterday for a briefing from the prime minister and chief of staff Gavin Barwell on the "customs partnership", believed to be Mrs May's preferred option, under which the UK would collect tariffs on the EU's behalf, and the "max fac" scheme, which involves the use of technology to minimise friction at the Irish border.
But EU chief negotiator Michel Barnier is reported to have told a Brussels meeting that it was not worth fighting about the two UK proposals, as neither of them is "realistic".
Today's 90-minute meeting of the cabinet's Brexit negotiations sub-committee heard presentations from Brexit Secretary David Davis and Cabinet Office minister David Lidington on the work completed so far by two ministerial working groups set up by Mrs May last week to look for improvements to the two schemes.
The meeting, attended by 11 ministers including Foreign Secretary Boris Johnson, was not asked to make a choice between the models.
No date has been announced for a further meeting.
Meanwhile, the Labour Party is launching a new parliamentary bid in London to force the government to release details of its proposals for post-Brexit customs arrangements.
It has tabled a motion in the House of Commons for debate tomorrow designed to break the "deadlock" over the issue.
The motion would require the government to release to parliament all papers prepared for the sub-committee on the two customs models, including any economic analysis.
Shadow Brexit secretary Keir Starmer said: "The government's Brexit strategy is in complete and utter deadlock.
"Nearly two years on from the referendum, ministers have still yet to agree what our future customs and trading relationship with Europe will look like after Brexit.
"Instead, the prime minister has wasted months pursing her two fatally flawed customs options and presiding over a government that is too busy arguing with itself to negotiate for Britain.
"If Theresa May is too weak to take that decision, then she should give Parliament the information to let it decide."
Scottish parlimanent votes against EU Withdrawal Bill
Members of the Scottish parliament have formally refused to grant consent to key Brexit legislation from the British government.
A Scottish Government motion, making clear the parliament in Edinburgh "does not consent" to the European Union (Withdrawal) Bill was approved by 93 votes to 30.
Despite the vote, Scottish Brexit Minister Mike Russell has vowed this will "not be the end of the process", as the two governments aim to settle their long-running dispute over where powers returning to the UK post-Brexit should be held.
If no deal can be reached, Westminster has the option of introducing the Withdrawal Bill against the wishes of the Scottish Parliament.
But it has never been forced to overrule Holyrood before, and such a move could spark a constitutional crisis.