It took little time for Labour and Tory supporters to gleefully declare that Ukip's bubble had burst after Lord Ashcroft published a poll showing the Tories 15 points ahead in the Newark by-election. If the party can't take seats off the government in mid-term, as the SDP did regularly in the 1980s, what kind of insurgency is it?
But while Westminster's desire to see the Farageists fail is an understandable one, Newark doesn't show that they have. For a start, the party's rating of 27 per cent represents a swing of 17.5 per cent since 2010, not unimpressive in what is only the 248th most "Ukip friendly" seat. That second place in a by-election is now viewed as a failure only shows how successful it has been in the last year. Look beyond Newark, and the signs remain encouraging for the party. Ukip was on 19 per cent in Ashcroft's national poll and is on 17 per cent in today's YouGov poll, its joint-highest rating ever.
A fairer test of Ukip's ability to win Westminster seats would be a by-election in one of its top 50 targets. What is clear is that, barring an unlikely meltdown, the party will have a decisive effect on the general election result. In 2010, it won 3 per cent of the vote, enough to deprive the Tories of up to 20 seats (there were 20 constituencies in which the party's vote exceeded the Labour majority). Should Ukip poll more than twice that (as it almost certainly will), and continue to take votes disproportionately from the Conservatives, it could do what Tories fear most and deliver victory to Ed Miliband.