By BLOOMBERG

LONDON • Prime Minister Theresa May said she is weighing a plan that would keep the UK bound to European rules for longer, in an attempt to break the deadlock in talks. May confirmed yesterday that she is considering extending the 21-month transition — the grace period that’s due to kick in on Brexit day and maintain trading and market rules unchanged.

“A further idea that has emerged is to create an option that extends the implementation period for a matter of months,” May told reporters in Brussels yesterday. “This is not expected to be used because we are working to ensure that we have the future relationship in place by the end of 2020.”

May signalled her willingness to give ground on transition during talks with fellow European Union (EU) leaders at a summit in Brussels on Wednesday. European Parliament President Antonio Tajani confirmed the issue was discussed between the 28 leaders.

The move, which would effectively prolong the terms of Britain’s EU membership, could come at a high political price in London, with the idea outraging Brexiteers in May’s Conservative Party.

“She is stalling,” Nadine Dorries, a pro-Brexit member of Parliament, said on Twitter. “It’s time to stand aside and let someone who can negotiate get on with it.”

“We are working with EU to deal with this issue of ensuring that if there is a gap between the end of the implementation period and the point when the future relationship comes in — and we don’t expect a gap to exist — we want to ensure there’s no hard border between Ireland and Northern Ireland,” May said.