LONDON (Reuters) – The opposition Labour Party will propose changes to the government’s EU repeal bill to ensure it does not exclude Britain remaining in the single market and customs union as part of a transitional Brexit period, The Times reported.

On Thursday, British members of parliament will hold their first full parliamentary debate on legislation dubbed the ‘Great Repeal Bill’ which will sever the country’s ties with the European Union.

Their first opportunity to put forward amendments to the bill, either proposing changes or adding new clauses, comes at a later stage.

Labour will call on Prime Minister Theresa May to make a series of changes including allowing parliament to replicate any new EU laws on employment rights, the environment and consumer protection, The Times reported, citing a letter sent by Labour’s Brexit spokesman to minister David Davis.

The party, led by leftist Jeremy Corbyn, will also say that Britain should continue to participate in the customs union, single market and the European Court of Justice during a transitional period. It is hoping to attract support from pro-European Conservative MPs.

Labour did not offer an immediate comment when contacted by Reuters on Saturday.

The party said last week that it wanted to keep Britain in the European single market and customs union for a while after Britain formally leaves the EU in 2019, offering an alternative to the Conservative government’s stance.

The legislation’s passage through parliament could make or break May’s future after she lost her outright parliamentary majority in a June snap election, reopening the debate on the nature of Brexit.