British prime minister Theresa May will today offer the leaders of Northern Ireland, Scotland and Wales a formal role in shaping Britain's strategy for leaving the European Union.

At a meeting in London with the leaders of the three devolved administrations, including Arlene Foster and Martin McGuinness, the British prime minister will propose a new forum chaired by Brexit secretary David Davis.

Ms May said the Joint Ministerial Committee (EU Negotiations) would give Northern Ireland, Scotland and Wales an official channel to influence Brexit negotiations before they start next spring.

The forum would meet for the first time by the end of November and at least once more by Christmas, as negotiations progress in advance of article 50 of the Lisbon Treaty being triggered before the end of March 2017.

‘Opportunities’

Ms May said the new forum would allow the devolved administrations put forward their proposals “on how to seize the opportunities presented by Brexit and deliver the democratic decision expressed by the people of the UK”.

She is expected to say at today’s meeting that no final decisions have been taken and that how the UK leaves the EU will not boil down to a binary choice.

Mr McGuinness said yesterday he would tell Ms May that “any attempt to drag the North out of the EU” represented a fundamental change in the constitutional position and an undermining of the spirit of the Belfast Agreement.

“I will make clear . . . the democratic imperative to recognise and respect the vote in the north to remain in the EU in the upcoming negotiations process,” he said.

The first ministers of Scotland and Wales are pressing Ms May to produce a clearly mapped-out programme of the devolved administrations’ involvement in the talks process, with a vote in their assemblies before article 50 is invoked.

Meanwhile, former taoisigh Bertie Ahern and John Bruton will be in London tomorrow to give evidence to a House of Lords committee on the impact of Brexit on UK-Irish relations.