Theresa May and Jeremy Corbyn have refused to take part in a TV leaders' debate on May 18, but look set to avoid the embarrassment of being "empty chaired".
ITV confirmed plans for a televised showdown between political leaders in the run-up to the General Election, but the Prime Minister and Labour leader have ruled out being involved.
The broadcaster has asked the leaders of the seven parties that were represented in its 2015 debate, the Conservatives, Labour, SNP, Liberal Democrats, Ukip, Plaid Cymru and the Greens, to take part.
But a Tory source said the party was "unwavering" in its opposition to the Prime Minister taking part in a debate.
A spokesman for Mr Corbyn said: "Jeremy will not take part in an opposition leaders' debate.
"The British people have the right to see a head-to-head debate between the only two people who could form the next government and the Prime Minister's refusal is a sign of weakness, not of strength."
Broadcasters have come under pressure to "empty chair" leaders refusing to take part in debates, but an ITV source indicated that "we will have the right number of podiums for the people who are there".
Both Lib Dem leader Tim Farron and Ukip's Paul Nuttall have confirmed they will take part.
A Lib Dem spokesman said: "Tim will be taking part in the debate and is looking forward to the opportunity to make the Liberal Democrat case.
"We believe this election is an opportunity to change the direction of our county.
"We expect our hard-Brexit opponents, Labour, Ukip and the Prime Minister, Theresa May to all take part and make their opposing case. Otherwise, we expect ITV to empty chairs them.
"Tim believes, in politics, you must have the courage of your convictions. Let's see if May and Corbyn feel the same."
A Ukip spokesman said: "Mr Nuttall is delighted to be able to present Ukip's positive vision for a UK that is free, prosperous, secure and at ease with itself and the world.
"It's just a shame that Mrs May is too arrogant to present herself to the public for scrutiny and Mr Corbyn doesn't trust himself not to become an even greater embarrassment in debate."
As well as the debate, ITV will broadcast prime-time 30 minute Tonight Election Specials, starting with Mr Farron on May 8, followed by further films featuring interviews with Mrs May, Mr Corbyn, Mr Nuttall, the SNP's Nicola Sturgeon, Plaid Cymru's Leanne Wood and Green co-leader Caroline Lucas, focusing on their lives, interests and policies.
There will also be debates between leaders in Wales, Scotland and Northern Ireland.
ITV's director of news and current affairs Michael Jermey said: "We have a strong record on organising debate programmes and giving viewers the chance to put their questions straight to the politicians.
"The ITV Leaders' Debate moderated by Julie Etchingham and the debates in the nations will give viewers an opportunity to get answers."
A Panelbase poll indicated 61% of Britons would watch a televised leader debate, and 52% would watch even if Mrs May refused to take part.
Panelbase surveyed 1,034 online between April 28 and May 2.