The sensible advice to the Tories after Eastleigh is, of course, 'don't panic'. The problem, however, is they already have. Indeed, they've been panicking about Ukip for well over a year now - which is precisely why they've ended up in this mess in the first place. And it's going to be difficult, if not impossible, to get out of it.

Conservative right-wingers - or at least those who are eurosceptic and worried about migration and multiculturalism - have long had a vested interest in talking up the threat from Ukip. For one thing they are genuinely (and, depending on your point of view, properly) convinced that naughty Nigel Farage may end up nicking enough votes off Tory candidates in marginal seats to see them lose out to their Labour or Lib Dem opponents. For another, they figure that, if they make this argument long enough and loud enough, the Tory leadership will harden its stance on the EU and on immigration and integration.

Superficially, the idea that the Conservative's best response to Ukip was to shift right seems to make sense. If you believe that by ignoring the latter's signature issues you create space which it will rush in to fill, then running hard on those issues is surely the right thing to do. This spatial model of electoral competition is pervasive - and presumably persuasive enough to help convince David Cameron to make his promise to hold an in/out referendum and Theresa May to trumpet her triumphs on immigration in the face of significant anxiety, even protests, on the part of business and universities.

But this spatial model is not the only one out there. Another take on all this comes out of research on both voting and political communication. This suggests that elections are, at least in part, won and lost according to the issues that voters see as most salient by the time they come to cast their ballots. To win, a party should try to frame the election in such a way as to ensure that it primes voters to think that the issues which it 'owns', rather than those owned by its opponents, are the most vital questions facing people as they head off to the polling station.

The problem, then, about the Tories accommodating response to Ukip over the last year or so that it has signalled to voters that the real issues right now are not just the perennial ones around the state of the economy and public services but also immigration, the EU, restoring traditional values in education, combating political 'correctness gone mad' and so on. Given that the Conservative lead over Labour on the economy and on public services is either tenuous or non-existent, and given the threat posed by Ukip on all these other issues, the emphasis on the latter rather than the former is understandable. But it has - as the result at Eastleigh suggests - ultimately proved counterproductive. Rather than shooting Nigel Farage's fox, all Cameron has done is feed it.

No-one plagued by the all-too-real urban cousins of that metaphorical pest needs to be told how difficult they are to get rid of once they've gained a foothold in your neighbourhood. And what, after all, can Cameron do now? Unless and until the economy improves and reforms to schools and hospitals turn out not to be as damaging as some predict, he can hardly dial down the rhetoric on any of the issues that also play well for Ukip - particularly when, at the same time, they play badly for Labour. If anything, the prime minister is going to be facing demands from within and without that he turn up the volume even louder.

It's an unenviable position. But he can't say he wasn't warned. Modernising Tories will no doubt be getting it in the neck over the next few days from those who blame their desire to detoxify the brand for giving Ukip the chance to capitalize on the inevitable confusion that change creates. But they can justifiably argue that that confusion would have been a price worth paying had it been temporary - which it would have been had Cameron and Osborne followed through on it and not allowed the economic downturn (and their own Thatcherite instincts) to knock them off the pragmatic, tolerant and centrist course on which they initially seemed to set out back in 2005.

That, however, was then, and this is now. Having run the economy into the ground, risked their already shaky reputation on the NHS, gone for gay marriage at the same time as seeming to beat up on a range of other minorities by pursuing the politics of us and them, and upped the ante impossibly on Europe, the Tories are now in the worst of all worlds. That it is a world mainly of their own making should come as no consolation at all.

Follow Tim Bale on Twitter: www.twitter.com/ProfTimBale