Today at Prime Minister's Questions Labour leader Ed Miliband challenged the Prime Minister to take part in head-to-head debate one week before election day.
Cameron said any TV debate should happen before the short General Election campaign so as not to distract from the campaign proper.
"I have been very clear, I have said get on with the debates before the election campaign begins, I think we should start now", Cameron said.
Labour were quick to accuse the Prime Minister of trying to "scupper the negotiations and sink the debates".
If the broadcasters and the other party leaders agree to the Tory leader's offer, the debate would take place before the 30 March when Parliament is dissolved.
The Daily Telegraph reports that Craig Oliver, the PM's director of communications, sent a letter to the chair of the broadcasters’ leaders’ debates committee Sue Inglish delivering the ultimatum.
The letter says:
This is our final offer, and to be clear, given the fact this has been a deeply unsatisfactory process and we are within a month of the short campaign, the Prime Minister will not be participating in more than one debate.