LONDON (REUTERS) - Legislation authorising the British government to begin the legal process of exiting the European Union (EU) will be debated in Parliament on Jan 31 and Feb 1, the government said on Thursday (Jan 26), outlining the first steps of the lawmaking process.

Earlier this week, Britain's top court ruled that Prime Minister Theresa May must seek parliamentary approval to trigger Article 50 of the EU's Lisbon Treaty, rejecting the government's argument that it should be able to do so unilaterally.

The ruling is not expected to derail Mrs May's plans to trigger Article 50 by the end of March, starting two years of complex negotiations with the EU on the terms of Britain's exit and its new trading arrangements.

However, opposition parties have said they will try to amend the legislation to make the government reveal more details of its Brexit plans.

The Bill seeking lawmakers' approval will be published at around 1230GMT (8.30pm Singapore time) when it is formally introduced to Parliament.

It will be debated for two days next week and another three days between Feb 6 and Feb 8 as part of the normal legislative process.