By Elizabeth Piper and Kylie MacLellan
LONDON (Reuters) - The British parliament was set to back Prime Minister Theresa May's Brexit timetable on Wednesday after she headed off a rebellion in her Conservative Party over a lack of insight into the government's strategy to leave the European Union.
May has come under pressure from lawmakers, businesses and investors to set out at least a broad picture of how she sees Britain's future relationship with the EU. She says giving too much away could weaken Britain's hand in the country's most important negotiations since World War Two.
In a sometimes rowdy session in parliament, the opposition Labour Party pressed its motion for a detailed plan setting out the government's negotiating stance in its talks with the bloc before triggering the formal divorce procedure.
But by agreeing to the government's demand for parliament to endorse May's timetable to trigger Article 50 of the EU's Lisbon Treaty by the end of March, Labour lawmakers were accused of falling into a trap -- allowing ministers to invoke the divorce without consultation.
Labour Brexit spokesman Keir Starmer denied it was a vote on Article 50 but rather one on forcing the government to offer a plan with "enough detail and clarity to end the circus of uncertainty" over Britain's future ties to the EU's single market of 500 million consumers.
"Asking for a plan setting out the objectives is not to seek to undermine the UK's negotiating hand nor is it to seek a running commentary, but it is in fact to have clarity, scrutiny and accountability," he said.
He said that if the government failed to a sufficiently detailed plan, Labour would challenge it again, he said, adding that the party aimed to head off a "hard Brexit.
The answer from government was clear -- it was offering information when it could and it would produce a plan. What was not clear was what would be included in that plan.
"I will make as much information as possible available without prejudicing our negotiating position," said David Davis, May's Brexit minister.
Some lawmakers have said they will oppose the motion, but with Labour on board, May should get parliamentary backing for her plan to trigger Article 50 by the end of March.
May hopes to stick to her timetable but faces obstacles after a court ruled that the government needs parliament's assent to invoke Article 50. The government is challenging that ruling in the Supreme Court.
Earlier, government minister David Lidington said lawmakers who planned to vote against the government would "thwart the outcome of the referendum in the most profoundly undemocratic manner".
Also on Wednesday, a judge said that even if parliament did vote in favor of the March deadline, that would make no difference to his case that parliament, not ministers, had the power to authorize triggering Brexit talks. [nL5N1E237L]
(editing by Angus MacSwan)