THERESA May will attempt to get on the front foot over Brexit by publishing a White Paper, setting out the UK Government’s aims for Britain’s future relationship with the European Union.

After months of wrangling, the Prime Minister will next month produce the key policy document, said to run to more than 100 pages and cover issues like financial services, regulatory divergence, aviation and fishing.

Agreement to produce the White Paper came earlier on Tuesday. It will be published ahead of the crunch European Council on June 28/29. The Brussels Commission is keen for Britain to spell out its plan for future customs arrangement at the EU summit.

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David Davis, the Brexit Secretary, described the policy document as the Government’s “most significant publication on the EU since the referendum” in 2016.

Another Cabinet insider said it would at last "allow the UK to go and actually negotiate".

Crucially, the White Paper will contain the Government’s proposal for future customs arrangements.

More discussion was had yesterday about the two suggested options but still without a firm decision taken. One is expected in the next week or so following “refinement” of the options by civil servants and ministers.

The 90-minute meeting of the Cabinet's 11-strong Brexit negotiations sub-committee heard presentations from Mr Davis and David Lidington, the Cabinet Office Minister, on the work completed so far by two ministerial working groups.

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On Monday, scores of Conservative MPs were invited to a Downing Street presentation, where they were briefed by the PM and her Chief of Staff Gavin Barwell on the two customs options.

A tweaked version of the “maximum facilitation” plan, heavily reliant on modern technology to secure as frictionless trade as possible, is thought to be the likelier outcome despite Mrs May having initially preferred the customs partnership option, famously described by Boris Johnson, the Foreign Secretary, as “crazy”.

Michel Barnier, the EU’s chief negotiator, is reported to have told a Brussels meeting that it was not worth fighting over the UK’s two proposals as neither was "realistic".

Labour’s Paul Blomfield said it was “deeply disturbing” that, after yet another meeting of the so-called War Cabinet, ministers could still not agree on the most fundamental of Brexit issues.

“Ministers have finally agreed to publish a White Paper on the Government’s negotiating position but they still don’t know what it will say,” he declared.

“Labour called for a White Paper before Article 50 was triggered. However, ministers have wasted months arguing amongst themselves rather than negotiating in the national interest.”

Mr Blomfield said the continuing failure of the Cabinet to come up with a future customs plan underscored the “deep division at the heart of Government on the most basic of issues”.

He added: “Whether those divisions can be resolved in the next month remains to be seen. If the Cabinet can’t take the decisions, Parliament will.”

Today, Labour will launch a new parliamentary bid to force the Government to release details of its proposals for the post-Brexit customs arrangements on the Irish border.

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It has tabled a Commons motion for a debate designed to break the "deadlock" over the so-called "customs partnership" and "maximum facilitation" models.

It would require the Government to release to Parliament all papers prepared for the Cabinet Brexit sub-committee on the two customs models, including any economic analysis.

The move is the latest in a string of Labour motions using an arcane parliamentary procedure to make the vote binding on the Government by issuing a "humble address" to the Queen asking her to require ministers to comply.

Sir 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.”

The Shadow Brexit Secretary added: "If Theresa May is too weak to take that decision, then she should give Parliament the information to let it decide."