Pro-Europe Labour and Conservative MPs have been handed a Brexit-related victory after Theresa May promised to publish a white paper on her plans to split from the EU.

The Conservative premier confirmed the move at prime minister's questions on Wednesday afternoon (25 January).

But May was evasive over the timetable of the white paper after Labour leader Jeremy Corbyn raised the issue.

"My question wasn't complicated, I just ask when the white paper will come out," the left-winger protested.

"In his reference to the timing issue, these are actually two separate issues," the prime minister replied.

"The House has overwhelmingly voted that the Article should be triggered before the end of March 2017.

"Following the Supreme Court judgement, a bill will be provided for this House and there will be the proper debates in this chamber and in the other place [House of Lords] on that bill.

"There is then the separate question of actually publishing the plan I have set out, a 'Bold Vision for Britain for the Future', I will do that in a white paper."

The development comes after Brexit Committee chair Hilary Benn and Sir Keir Starmer, Labour's shadow Brexit secretary, pressed David Davis on the issue in the Commons yesterday.

The Brexit Secretary, speaking just after hours after the Supreme Court's Article 50 judgement, refused to commit the government to a white paper.

He instead argued that May had outlined her 12-point Brexit plan in her Lancaster House speech on 12 January.

"That timetable has given valuable certainty to citizens and business in the UK and across Europe, it's understood by our European partners and provides a framework for planning the negotiation ahead," Davis said.

But the pressure mounted on May and Davis as Conservative MPs, including former ministers Nicky Morgan and Anna Soubry, joined with Labour in calling for a white paper.

The climb down comes ahead of the prime minister's visit to Washington to meet Donald Trump on Friday.

The leaders are expected to discuss a potential trade deal between the UK and US, with May hoping to secure a "bespoke" arrangement with the EU which would allow Britain to broker its own trade deals.

"I'm pleased I'm able to meet President Trump so early in his administration. That is a sign of the special relationship between the UK and US, a special relationship he and I intend to build," the prime minister said.

"I'm not afraid to speak frankly to a President of the US – I'm able to do that because we have that special relationship."