It’s being billed as the last roll of the dice in Rochester and Strood:

‘Conservative strategists have noted how house prices stagnated in the London borough of Barking and Dagenham after the BNP won swathes of council seats in 2006 and middle class families moved out, while values in surrounding areas surged…”The danger is if you vote Ukip, the value of your house will go down,” said Charles Walker, the MP for Broxbourne, who was campaigning in the town this afternoon.’

I mean, seriously? Is this the pitch?

Attacking Mark Reckless as somehow being of inappropriate background to be MP for Rochester and Strood – despite the fact he was selected three times to stand for the job by the local Conservative Association – was a misfire. But this latest argument is an outright dud.

For a start, there’s no sound basis for it. UKIP are many things, and have many failings, but they are not the BNP (either in reputation or in reality). The polls show all too clearly that they don’t have the toxicity of that fascist party, either – and it was toxicity which drove people to leave Barking and Dagenham.

The fact that our by-election candidate won’t be drawn into discussing the claim, and that it has been communicated through Charles Walker rather than a visiting Cabinet minister, suggests that at least some in the operation are aware of how dicey it really is.

Worse, it’s sufficiently implausible that it hands yet another opportunity to UKIP to play up their central message – that the ‘LibLabCon establishment’ are desperate to stop their revolution at any cost, and that in itself is a sign of how important and righteous the insurgency is. As predictably as the head of a pint rises to the top, that is exactly the response Farage has given to the house price claim. Did our campaign really need to hand him another opportunity to make the anti-politics argument? The plausibility and morale boost that an argument like this offers to UKIP should not be underestimated.

The justification for using this line, such as it is, appears to be that some people have mentioned it on the doorstep. As we all know, voters mention lots of things on the doorstep – it doesn’t mean it should be your new campaign tag. Quite what convinced those running the campaign that this was a wise thing to adopt we have yet to learn.

There are plenty of reasons not to vote UKIP – Tim laid out some of them last week, we’ve been exploring their policy failings on our new UKIPWatch blog and UKIP themselves offer several new examples every week – but this isn’t one of them.

More importantly, there are a myriad of positive reasons to vote Conservative instead. Crime is way down. Jobs are way up. Wages are starting to overtake inflation, as the pay-off for the tough work on the deficit and the economy finally arrives. The Conservatives remain the only actual way to secure an In/Out EU referendum.

If you prefer a negative reason, Ed Miliband gets steadily more dangerous for Britain – and Nigel Farage has publicly stated his willingness to help him get into power. If there’s any genuine way a UKIP MP could harm your house price, it’s by putting Labour back into Downing Street and thus helping them to wreck the economy yet again, not by sheer force of reputation.

The election battle in every parliamentary seat matters, because they will collectively decide the next government – unlike Farage’s description of the European elections, they are not a “free punch” against Westminster.

If, as the polls and the betting markets suggest, we lose Rochester and Strood on Thursday then the local Association will strain every sinew to win it back in May. I suspect they’ll do it by making a positive case for voting Tory and a serious case against voting UKIP – not by making flimsy claims like this.