Britain’s parliament approved legislation on Monday that gives lawmakers the power to scrutinise and even change Prime Minister Theresa May’s request that the European Union agree to delay Brexit until June 30.

May has already asked Brussels to extend Britain’s EU membership to allow talks with the opposition Labour Party in search of different exit plan – a last-ditch attempt to keep control after parliament rejected her Brexit deal three times.

But lawmakers want additional legal guarantees against a “no-deal” exit happening on April 12 – the current exit day – and have crafted a law forcing ministers to consult with parliament on Tuesday before May goes to Brussels.

“Both houses of parliament have tonight strongly made clear their view that a no deal would be deeply damaging to jobs, manufacturing and security of our country,” said lawmaker Yvette Cooper, one of those responsible for proposing the legislation.

The bill gives lawmakers the chance to make legally binding changes to May’s requested departure date during a debate scheduled to last 90 minutes on Tuesday. The prime minister would retain some freedom to agree a different date with the EU.

May is due to travel to Paris and Berlin on Tuesday to press her request for a short delay, before it is formally discussed by EU leaders at a special summit on Wednesday.

The bill passed through the Commons by a single vote last week and was then approved with minor changes in the House of Lords, an unelected body whose role is to refine and scrutinise legislation, which the Commons then had to sign off on.

The passage of the bill represents a significant blow to May’s authority, overturning the long-standing convention that the government has sole control of the agenda in parliament, allowing it to control what laws are passed.

It also creates another flashpoint in a deeply divided body of lawmakers that could undermine May’s attempts to persuade Brussels she can get parliament to back a Brexit deal if the EU gives her more time.

The government had warned that the legislation was poorly drafted, rushed through parliament and set a dangerous constitutional precedent. Pro-Brexit lawmakers also fiercely opposed the bill.

“(It) is like tossing a hand grenade into our constitutional arrangements,” said eurosceptic Conservative lawmaker Bill Cash.