Britain's Prime Minister Theresa May attends a news conference during the EU Summit in Brussels, Belgium, March 9, 2017. REUTERS/Dylan Martinez

LONDON (Reuters) - Prime Minister Theresa May will set out how her government plans to restore sovereignty over Britain’s laws on Thursday, publishing a detailed paper on ending “the supremacy of EU lawmakers”.

A day after the British leader is due to launch formal divorce negotiations with the European Union by triggering Article 50 of the bloc’s Lisbon Treaty, May’s government will publish a formal policy document on its “Great Repeal Bill”.

The repeal bill will convert EU law into British law, a process the government hopes will ensure continuity for businesses, workers and trade in a process some experts say could be more complicated than it sounds.

A government source said that this week would mark “a defining moment in this country’s history” when May invokes Article 50 on Wednesday to open the way for formal negotiations to leave the EU following a referendum last June.

“But a strong, sovereign country needs control of its own laws. That, more than anything else, was what drove the referendum result: a desire for the country to be in control of its own destiny,” the source said.

Thursday’s publishing of the repeal bill white paper -- a policy document setting out proposals for future legislation -- is part of May’s attempt to reassure business and workers that they can plan for Brexit with some certainty.

Some companies have expressed fears that an expected two years of talks after the triggering of Article 50 could easily get bogged down by disputes and that the country will crash out of the EU in a so-called hard Brexit with little in place to ensure to ensure there is no disruption to markets and trade.

David Lidington, leader of the lower house of parliament, said that much of the legislative work would involve small tweaks in the language used to make sure it relates to Britain.