There’s only one result that matters to UKIP in this election and that’s whether its leader Nigel Farage is elected in Thanet South. If he isn’t it could be game over for a party that has rattled the cage of the establishment parties for close on a decade. The reason? If he doesn’t win, Nigel Farage says he will immediately step down as party leader. UKIP isn’t quite the one man band it once was, but to pretend that a Farage resignation would be anything other than a disaster would be to be blind to some political realities.

The latest Survation poll puts UKIP nine points ahead of the Conservatives in Thanet South, although I should add the caveat that the poll was commissioned by a UKIP donor. The latest Ashcroft constituency poll, taken in November, puts UKIP one point behind his Tory opponent Craig Mackinlay. My gut instinct is that Farage will pull through – just – but it’s probably going to be very close.

So what constitutes a good performance for UKIP? They have been targeting forty seats with the hope, and perhaps expectation, of winning ten or a dozen. In reality, a lacklustre election campaign has meant that their realistic hopes boil down to perhaps 5-8 seats, although there remains a real possibility of them only winning one or two.

I’d be astonished if Douglas Carswell doesn’t retain his Clacton seat, but Mark Reckless in Rochester & Strood is in big trouble. Most of the money is on his Tory opponent Kelly Tollhurst to pull through. Tollhurst isn’t a strong candidate, but the Tories are putting huge resources into the seat to win it back.

Elsewhere, Essex remains the best hope for some UKIP gains, with Thurrock being the most likely win. Local boy Tim Aker is in a three way fight with Conservative Jackie Doyle-Price, the incumbent, and former Miliband adviser and Radio 1 Newsbeat journalist Polly Billington. Ordinarily Billington would have expected to walk this seat but her vote has disappeared as UKIP make strong headway in this Essex rust belt constituency. Aker is pugnacious, aggressive and determined and is odds on to win here unless enough UKIP voters can be frightened back into the Tory fold by threats of an SNP/Labour arrangement.

The other UKIP hope is in Castle Point, otherwise known as Canvey Island. The former MP here Robert Spink defected to UKIP back in the Gordon Brown years, although almost immediately then went independent. The current Tory incumbent Rebecca Harris ought to be very nervous about her future as UKIP has conducted a good campaign here and have high hopes. A UKIP win is certainly by no means impossible.

There are two seats in Lincolnshire which Nigel Farage has been confident of winning, but both seem to be slipping away now. Great Grimsby was there for the taking but UKIP has a disastrously unpopular candidate, the former Tory candidate in 2010 Victoria Ayling. Their campaign launch was slammed by the local media for its amateurishness and according to the latest Ashcroft poll they now trail an equally unimpressive Labour candidate, Melanie Onn, by a massive 17 points. Further down the coast in Boston & Skegness their 22 year old candidate Robin Hunter-Clark appears to be faltering in his campaign to win the seat from the Tories.

Back in the autumn UKIP nearly won the Labour seat of Heywood & Middleton in a by-election on the same days that Douglas Carswell won Clacton. The fact that they came within 617 votes of doing so wasn’t just a surprise to everyone else, it shocked UKIP too. The same candidate is fighting the seat and has been working hard to get those extra votes. His leader is confident he will, but I’m not so sure now.

Dudley North is another Labour marginal, currently held by Ian Austin, where UKIP are doing well. With the Tory candidate resigning in disgrace this could be UKIP’s for the taking. It’s a seat they haven’t bene shouting about and it’s rarely mentioned in the headlines, but it’s certainly one to watch on election night.

Another seat in which UKIP have more than a fighting chance is Great Yarmouth, although they have had candidate troubles there too. They have a strong local council presence, but in the end they will probably take enough votes from Labour to come second, but allow the Conservative Brandon Lewis to pull through.

Cannock Chase, Plymouth Moor View and South Basildon & East Thurrock are three other seats which are worth watching on election night.

For what it’s worth, I think UKIP will end up with a maximum of 5 seats, which are likely to be Clacton, Thanet South, Dudley North, Castle Point and Heywood & Middleton.