David Davis has pledged to share the Westminster government’s “latest thinking” on Brexit with the leaderships of Scotland, Northern Ireland and Wales, before the first meeting of a forum intended to allow the devolved administrations to help shape Britain’s strategy.

At the end of October, Theresa May promised Scotland’s first minister, Nicola Sturgeon, the Welsh first minister, Carwyn Jones, and Northern Ireland’s first minister, Arlene Foster, and her deputy, Martin McGuinness, a “direct line” to Davis, her Brexit secretary, saying it was “imperative that the devolved administrations play their part in making [negotiations] work”.

At the forum meeting on Wednesday, Davis will commit to sharing analysis undertaken by his department for exiting the European Union and to hosting further monthly meetings of the forum, formally named the EU negotiation joint ministerial committee.

Davis said” [The government is] determined to get a deal that works for all the parts of the United Kingdom. I want to ensure the free and trusted flow of important information between all parties involved. So we are asking the devolved administrations to bring us their analysis that will help shape our priorities for the negotiation with the EU, and we will share our latest thinking.

“The UK has chosen to leave the EU and we are determined to work closely with the governments of Scotland, Northern Ireland and Wales in making a success of it.”

On Tuesday, Sturgeon announced that the Scottish government would seek to join the next legal battle over MPs’ right to vote on article 50, after the UK government’s defeat in the high court last week.

She said Scotland’s lord advocate would lodge a formal application to intervene in the Westminster government’s supreme court appeal against last Thursday’s ruling, which stated that MPs needed to vote on triggering article 50 to begin the process of leaving the EU.

Sturgeon, who has previously endorsed a proposal from Jones, the Welsh leader, that any planned negotiating package should be subject to a vote in all four UK parliaments and assemblies, said Holyrood should also be formally consulted on the decision.

This would mean the Scottish parliament voting on a legislative consent motion, under the parliamentary convention which requires that Holyrood agree to any changes in its powers and responsibilities. This does not amount to Holyrood having a veto on triggering article 50.

Sturgeon said that regardless of the legal outcome, politically she believed there should be a legislative consent motion before Holyrood. “It would be disrespecting the whole devolution settlement and the place that that convention has always had in the devolution settlement for a decision of this magnitude and with this degree of impact on our devolved responsibilities to be taken without the Scottish parliament being consulted,” she said.

The first minister said she believed members of the Welsh and Northern Irish governments would take similar views of their own parliaments.

The Brexit case will be heard at the supreme court over the course of four days between 5 and 8 December. The Welsh government has already declared its intention to intervene in the case. Appeals by Northern Ireland groups arguing that parliament and the assembly in Stormont should ratify the triggering of Brexit may also be joined to the supreme court case.

