Yesterday's Populus poll in The Times shows a seven per cent hit on support for the Liberal Democrats, i.e., around a third of their declared support. This is quite surprising given that (a) they have not had any real serious cases, the odd bit of interior decoration aside and (b) they are the party which has taken constitutional reform seriously (perhaps too seriously, given that the merits of different systems of PR is a real topic for anoraks).
Presumably voters see them as much a part of a failed political class as the two main parties. What one is seeing is a general anti-incumbency effect, often regardless of the merits of the incumbent. Voters are flocking to UKIP which has been beset with its own expenses scandals.
We are also seeing celebrities trying to fill the vacuum. I am not sure how being a successful television personality qualifies one for dealing with the complex issues that beset modern government, although Esther Rantzen could claim to have tackled some serious policy issues as well as celebrating odd shaped vegetables.