The BBC and ITV have both agreed to host Conservative Prime Minister Theresa May and opposition Labour leader Jeremy Corbyn in a televised debate on the deal that May agreed for Britain to leave the EU.

The broadcasters said May has accepted the BBC's offer of a debate at 9:00 pm on December 9, while Corbyn prefers rival ITV's offer to host the debate an hour earlier to avoid a clash with the final of the hugely popular ITV programme "I'm A Celebrity ... Get Me Out Of Here!"

The BBC tweeted that May had "accepted the BBC's offer to take part in a debate" on December 9, two days before parliament votes on the deal.

"We're delighted she's agreed and hope to hear soon from the Labour party," it said, adding that it was discussing the format of the debate with both parties.

Corbyn told ITV's This Morning programme that he preferred the ITV time slot "because it's not inconveniencing people who want to watch other things later in the evening."

"One should always have respect for the viewers and also we want to get the widest possible audience," he said.

Two smaller opposition parties, the Liberal Democrats and the Scottish National Party (SNP), demanded a role in the TV debate.

"Jeremy Corbyn and Theresa May can offer only a narrow debate," said Ian Blackford, the SNP's leader in the British parliament, in a statement. "All options - including remaining in the EU - must be given voice," Blackford said.

Neither May nor Corbyn supports the idea of holding another referendum on the Brexit deal, which both the SNP and the Liberal Democrats back.

The Liberal Democrats accused May of "running scared of the real opposition."

"This would be an absolute travesty," Liberal Democrat leader Vince Cable said in a video message.

"Neither of them believes that the public should be able to have the final say on the deal, including the option of remaining in the European Union," Cable said.

May confirmed Tuesday that she had challenged Corbyn to a debate, amid her campaign to convince lawmakers from all parties to support her hard-won deal.

She has started touring the country to rally the public behind the deal.

May has told lawmakers they face a choice between accepting the deal or going "back to square one." She was criticized for refusing to take part in a customary televised debate before a snap general election that she called last year.