We’ve still a fortnight to go until the Rochester & Strood by-election. If it feels like the campaign has gone on for months, that’s because it has. By the time polling day arrives, it will be almost two months since Mark Reckless announced he was defecting to Ukip and seeking re-election.

Opting for a long campaign does not seem to have helped the Conservatives. Each sequential opinion poll conducted in the constituency has shown an increase in Ukip’s vote share: from 40% to 43% to 48%. Ukip’s lead over the Tories has also gone up, from nine points to 13 points to 15 points. At the same time Labour’s share has gone down, from 25% to 21% to 16%. Given the Tories’ vote share has remained pretty static (31%, 30%, 33%), it seems that Labour supporters have been shifting to Ukip in growing numbers.

Reports from the seat have carried anecdotal evidence of this occurring, sometimes for tactical reasons – Labour voters wanting to ensure the Tories are given a drubbing – and sometimes for genuinely ideological reasons, as people switch to Ukip as they believe the party is best aligned with their own opinions.

Initially I thought Mark Reckless would struggle to win the seat. It now looks like I was wrong, and that I misjudged the extent to which the Conservatives would succeed in painting Reckless as a traitor and a dishonorable candidate.

There is now a growing expectation that Ukip will win and win comfortably. Curiously, this expectation is not being energetically disputed by the Tories. I suspect the party is attempting to “price in” a defeat – in other words, to dilute the shock of a Ukip victory. But that won’t stop Ukip getting the one thing it needs even more than a second MP: publicity.

How poorly Labour does in the by-election, and how atrociously the Liberal Democrats perform, will be two more aspects to this story worth noting. There are 13 candidates standing, which could mean the Lib Dems end up fifth or even sixth. Here’s the full list:

• Mike Barker (Independent)
• Christopher Challis (Independent)
• Hairy Knorm Davidson (Loony)
• Jayda Fransen (Britain 1st)
• Stephen Goldsbrough (Independent)
• Clive Gregory (Green)
• Geoff Juby (Liberal Democrat)
• Naushabah Khan (Labour)
• Nick Long (People Before Profit)
• Dave Osborn (Patriotic Socialist)
• Mark Reckless (Ukip)
• Charlotte Rose (Independent)
• Kelly Tolhurst (Conservative)

As the results will be announced in alphabetical order, we’ll have to wait until the very end of the declaration to find out exactly how far behind Ukip the Tories have come.