Britain's prime minister said on Thursday the United Kingdom may choose to be bound by European Union rules and regulations for longer than the planned two-year transition period that will follow it leaving the trading bloc at the end of March.

Theresa May, who is negotiating the terms of the divorce deal with EU leaders, said the two sides could agree to extend the transition period "by a matter of months" to allow more time for talks.

The UK and EU want an amicable deal to follow their divorce and have previously agreed that, no matter what deal they agree upon, they will continue to effectively function as if the UK is a member of the EU for two years after the UK leaves, to allow all sides to transition to the new arrangement.

"A further idea that has emerged, and it is an idea at this stage, is to create an option to extend the implementation period for a matter of months," she told reporters in Brussels after meeting EU leaders and again failing to solve the final sticking point – the future of the border between Ireland and Northern Ireland. Ireland will, of course, remain within the EU but neighboring Northern Ireland, a UK province, will leave at the end of March. Officials in both the UK and the EU want to avoid a so-called hard border, with checkpoints and customs functions, because the division of the island caused political unrest for decades and because today's soft border has greatly eased that tension.

May's suggestion that the transition period could be extended beyond the planned two years has not gone down well among some MPs in her party who want a speedy exit.

Former minister Nick Boles said on BBC Radio 4's Today program it was a "desperate last move" and that May was losing the support of her party. But May says she still hopes to thrash out a deal and any extension may not be necessary.

"The point is that this is not expected to be used because we are working to ensure that we have that future relationship in place," she said.

So far, there is no word on how much the UK might have to pay to extend the transition period. Reuters reported Cabinet Office Minister David Lidington as saying the figure will be "teased out" during talks.

Sky News reported on Thursday that a Brexit summit planned for November has been scrapped and that leaders will next meet on Dec 13 and 14.