May's plans to start the formal divorce procedure from the European Union by the end of March were dealt a blow last week when England's High Court ruled that her government must seek parliamentary approval for triggering Article 50.
May wants government, not parliament, to shape Britain's approach to leaving the EU and has said she will appeal the ruling in Britain's highest court - a stance her ministers and aides stuck to on Monday, avoiding any comment on the report.
Sky News quoted sources as saying the government was preparing a bill, legislation that will have to be considered in both houses of parliament in what could be a lengthy process and potentially delay May's timetable.
May's spokesman told reporters the government was focused on winning its appeal to the Supreme Court next month and meeting the March deadline - an argument repeated by her minister responsible for Brexit, David Davis.
Davis also told a rowdy session in parliament that the court's decision may not come until January.
The court ruling has stirred passions in Britain just over four months after 52 percent of voters supported leaving the EU in a referendum which deepened splits in the country and gave voice to resentment - mirrored across Western Europe and the United States - with a ruling elite seen as out of touch.
One lawmaker from the ruling Conservative party resigned last week over May's approach and dozens of others hope to soften the terms of Britain's departure.
Several accused the government on Monday of undermining democracy by trying to bypass parliament, most of whose members had favoured a vote to remain in the EU.
"The government has approached its task in the wrong way and its approach is now unravelling, and I am afraid to say it's unravelling in a most ... ugly way," said Keir Starmer, the opposition Labour Party's Brexit spokesman.
"Only parliament can make and repeal laws."
Some said they wanted to know the government's stance on the EU's lucrative single market of 500 million consumers - something Davis said he would make public "in due course".
But Davis, a leading campaigner for Brexit, repeated May's mantra that the government would deliver "the will of the people". Although willing to consult lawmakers, he said the prime minister would not be forced to reveal her hand.
"We won't achieve a good negotiation outcome if this is a negotiation being run by 650 people in this House of Commons. No negotiation in history has been run that way," Davis said.
"Indeed if parliament insists on a detailed minimum negotiating position that will quickly become the maximum possible offer from our negotiating partners."
http://uk.reuters.com/article/uk-britain-eu-may-bill-idUKKBN132137
