Ukip leader Nigel Farage has repeatedly challenged the Prime Minister to a televised debate.
His most recent call to face Cameron on air came last week in response to claims he was "chicken" for ruling out a run at Parliament in the Newark by-election.
The Ukip leader said: "Mr Cameron said ... that I was a chicken. Well, I'll tell you what Dave, why don't you come on telly and do a debate with me?"
More top news
Staying cloudy across southeastern areas throughout the night with some light rain at times.