British parliament to hold Brexit debate

British MPs will hold an unscheduled sitting day in parliament to discuss Brexit as the EU's deadline for a withdrawal deal to be approved looms.

The British government says it plans to hold a new Brexit debate in parliament, but hasn't confirmed whether it will call a third vote on its twice-rejected EU divorce deal.

House of Commons Leader Andrea Leadsom says MPs will hold an unscheduled sitting day on Friday to debate a Brexit motion.

The EU has given Britain until Friday to approve the Brexit deal and ensure an orderly departure from the bloc on May 22.

But Prime Minister Theresa May is still struggling to win over MPs, who have twice rejected the deal by large margins.

And the House of Commons Speaker has said the government cannot bring the rejected deal back a third time unless it is substantially changed.

"We recognise that any motion brought forward tomorrow will need to be compliant with the Speaker's ruling," Leadsom told parliament on Thursday.