May has to get the bill approved by both chambers of parliament well in advance of Britain’s exit on March 29, 2019, but the House of Lords, the unelected upper house, is demanding major changes that will force a showdown over coming weeks.
The Lords voted 294 to 244 in favour of a change to the bill which would force the government to maintain the EU’s environmental principles. The government argues that Brexit will allow Britain to improve environmental protections through separate legislation.
May’s Conservative government has already suffered high- profile defeats on core Brexit issues such as whether Britain should leave the EU’s single market and customs union.
While the more powerful House of Commons can overturn the changes, they may embolden rebels in May’s own party who favour a softer EU exit.
Ministers have accused the House of Lords, where the Conservatives do not have a majority, of making unnecessary changes and have indicated they will fight some of them back in the Commons.
That process, known as ‘ping pong’, is not yet scheduled, but will be a key test of May’s ability to govern effectively and to deliver on her Brexit plans with just a slim working majority in the Commons, where she relies on the support of a small Northern Irish party.
Reporting by William James. Editing by Andrew MacAskill and Gareth Jones