The British government is preparing the first draft of a new bill to trigger the formal procedure to leave European Union, Sky News reported on Monday citing sources.
England's High Court ruled last week that Theresa May's government must get parliamentary approval to trigger Article 50 of the EU's Lisbon Treaty, a blow to the prime minister's plans to launch the divorce process by the end of March.
May's aides say the government will appeal that decision in the Supreme Court and have declined to say whether ministers are contingency planning or drafting a bill that they will have to present to parliament if they lose that fight.
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.
A spokeswoman for May did not immediately respond to a request for comment.
May's focus on ensuring the government has the lead on breaking with the European Union has angered some MPs, prompting one of her ruling Conservative party MPs to resign last week and deepening splits laid bare in the June EU referendum.
But while those who campaigned to stay in the European Union hope the court decision will soften the divorce terms for Britain, pro-Brexit campaigners and Britain's euro sceptic newspapers have attacked the judges for what they called a betrayal of the vote.
On Sunday, May expressed support for Britain's judiciary and the press but insisted she would lead the country out of the EU.
"While others seek to tie our negotiating hands, the government will get on with the job of delivering the decision of the British people," May said in a statement before leaving on a trade visit to India.