Oh dear - I've just watched the second leadership debate on The Politics Show where Chris Huhne was utterly blindsided by a very nasty briefing document written by his campaign office entitled 'Calamity Clegg'.

What followed was a new low in leadership campaign politics as Huhne first denied knowing anything about the memo - and then proceeded to parrot all the attacks on Clegg contained within it! Several times he even used the word "flip-flop" - are we borrowing from George W Bush's campaign playbook now?

It was a most unedifying spectacle as Huhne recited the attacks by rote - including yet again his discredited line on school vouchers - as both the interviewer and Clegg were unable to stop him talking despite dozens of attempted interventions.

Clegg's response when he finally got to open his mouth was "this saddens me". He went on to chastise Huhne for attempting to manufacture synthetic differences between the two of them, including school vouchers, health insurance and Trident.

I have studiously avoided attacking either of the candidates thus far in this leadership election - but this makes me absolutely furious. I feel duty bound to warn the Huhne team that if they keep on dragging this campaign into an unsightly punch-up I will rapidly lose my sense of humour.

It's in their best interest too - I don't think any floating voters watching that just now will have been at all impressed by Huhne's display. If he wants Nick Clegg to come across as the more human, reasonable, and empathetic of the two he's going the right way about it!

Update: The World At One debate on Radio 4 wasn't much better: Huhne claimed that he'd apologised for the title of the briefing (if he has I didn't hear it), but still couldn't help himself from going on the offensive. I think the debate was epitomised by an exchange right at the end. While Clegg refused to be drawn into painting his comments on the Tories' advances on the environmental agenda as a criticism of Huhne, Huhne intervened with a poll saying we were still the most trusted party on the envionment and "we couldn't say that about Home Affairs, could we Nick?"

Oh dear.