As pre-election fighting intensifies, the two main parties were also at odds over proposals for a series of televised showdowns on key subjects including the economy, health and education.
Senior Labour sources said the Conservatives were "running scared" of holding a debate on economic policy between Alistair Darling, the Chancellor, and his Tory and Liberal Democrat opposite numbers, George Osborne and Vince Cable.
Andrew Marr's Sunday morning "AM" programme on BBC 1 is understood to be keen to host such a showdown – but David Cameron's party is said by Labour to be unwilling to take part.
The same is said to be true over plans for debates on education, health and crime. Last night a Conservative spokesman denied the party was running scared.

If they hold this debate, then whoever puts in a good performance is instantly going to be prime contender for next leader of their party in the event of a disappointing election performance. For Cameron that has implications, he looks likely to win but with a crappy majority, so he will be a weak leader. Now isn't the best time for him to line up his replacement.

Purely TV-wise, I think Cameron could clean up as the lowest common denominator. Tony became one of our most despised PMs ever, only for Gordon to be able to challenge him in that regard! And Clegg just hasn't got the overall showmanship needed to win an election in these oh-so-stylish days , so I could see Cameron winning by default. I'm basically saying a lot of people will have made their mind up already, and all Cameron has to do is not sweat too much

Don't get me wrong, that's not the way it should be at all, but I wouldn't be surprised if that's how it turns out...