Britain could leave the European Union without a Brexit deal on April 12 if its politicians fail to back Prime Minister Theresa May’s Brussels deal next week, EU leaders said after a crisis summit in Brussels on Friday (AEDT).

With just a week to go until Britain risks lurching out into legal limbo at midnight next Friday, EU leaders have given Mrs May an extra two months (until May 22), to leave if she wins next week’s vote in parliament.

European Council President Donald Tusk said the atmosphere at the emergency EU meeting was “much better than I had expected” and he was now “much more realistic”.

EU27 unanimously agrees on its response to UK’s requests. I will now meet PM @theresa_may. #brexit #euco

— Charles Michel (@eucopresident) March 21, 2019

Talks between the leaders ran late into the night (Thursday local time) amid reports of disagreement between some EU leaders about the details.

The conclusion was a deal that suggested that Britain could, if Mrs May fails, come back and ask for a much longer delay.

This would be on the condition – likely a major stumbling block – that it takes part in elections to the new EU parliament on May 23. For it to do so, British election law says that would have to be announced six weeks beforehand, by April 12.

If Britain does not call an EU election, it will be out.

“The European Council agrees to an extension until 22 May 2019, provided the Withdrawal Agreement is approved by the House of Commons next week,” the statement from EU leaders said.

“If the Withdrawal Agreement is not approved by the House of Commons next week, the European Council agrees to an extension until 12 April 2019 and expects the United Kingdom to indicate a way forward before this date for consideration by the European Council.”

Meanwhile, a British parliamentary petition calling for Mrs May to cancel Brexit by revoking Article 50 (the section of the European Union Treaty that governs how a country leaves the EU) has passed two million signatures.

Parliament’s petitions committee tweeted that the rate of signatures was “the highest the site has ever had to deal with” after the website crashed.

The rate of signing is the highest the site has ever had to deal with and we have had to make some changes to ensure the site remains stable and open for signatures and new petitions. Thanks for bearing with us.

— Petitions Committee (@HoCpetitions) March 21, 2019

At one point, the petitions committee said there were nearly 2000 signatures a minute.

Petitions on the website rarely lead to law changes, but are debated in parliament once they have more than 100,000 signatures.

-with AAP