Ukip leader Nigel Farage has confirmed he is to try and stand as an MP in the Kent constituency South Thanet, writing as such almost casually in his Independent column this morning despite the party refusing to confirm his intentions when they were splashed all over the papers last week.

So South Thanet's Conservative incumbent Laura Sandys might well be getting nervous. But where else are current MPs under threat from the “people's army?” We've profiled four likely locales below.

Thurrock

Thurrock is a name that springs straight to the lips of Ukippers when you ask where they've got a chance of winning. Notably, they placed first there in a recent Lord Ashcroft poll of voter intention. Dan Jukes, Elections Officer for Ukip's youth wing Young Independence (YI), tells me that it is one of only three seats (along with South Thanet in Kent and Gosport in Hampshire) which will benefit from YI campaigning “action days.” The incumbent, Conservative Jackie Doyle-Price, won with a miniscule margin in 2010. Her main rival, Labour's Carl Morris, is not standing this time. Ukip's candidate, Tim Aker, has maintained a relatively low public profile in the past, but he is at the heart of the party's 2015 election campaign. He is the head of Ukip's policy unit, and a genuinely powerful intellect in a party often criticised for prioritising the heart over the head. A champion darts player with a down to earth manner, he still won't look too lofty for Ukip's core vote. Look out for an interview with Aker in the September issue of Prospect, out next week, in which he discusses details of Ukip's manifesto publicly for the first time.

South Thanet

If Thurrock is the wonk's choice, now that Farage has thrown his hat in in South Thanet, expect the Kent seat to be where a lot of the media attention is focused. Writing in the Independent this morning, Farage says he didn't confirm his intentions before because Ukip members in the area still have to choose him at their hustings. That said, those members really would be fruitcakes and loonies if they turned down perhaps their party's best speaker and certainly their most recognisable figure. If Farage does get his chance, he'll have a decent shot. Ukip's 5.5 per cent result at the last election was earned by relative unknown Clive Broad. The constituency includes a lot of deprived seaside wards, an economic profile which has served Ukip well in areas like Margate and Portsmouth.

Great Grimsby

Matthew Goodwin, author of Revolt on the Right, has identified five seats in which Labour, rather than the Tories, should be worried about Ukip, of which he says Great Grimsby is by far the most likely win for Farage's party. Great Grimsby is a marginal seat for Labour, with incumbent MP Austin Mitchell just 2 percentage points ahead of his main rival, Victoria Ayling a former Conservative who defected to Ukip since the last election. Mitchell's majority has declined from 35 per cent in 2001 and 23 per cent in 2005. A working-class area with an 8 per cent unemployment rate (against a national rate of 6 per cent) and a 95 per cent white British population, it's demographically suited to Ukip.

Cambridge

This seat is the centre of Ukip's other big announcement of the week: that MEP and party communications chief Patrick O'Flynn will stand in Cambridge. Cambridge falls within the East of England European Parliament region, where Ukip saw their strongest performance in May's European Parliament elections (they took 34.5 per cent of the vote, as against 27.5 per cent nationally). The incumbent, Julian Huppert, is a Lib Dem, so Ukip will be hoping that party's staggering national unpopularity plays out at a local level in the same way as it did at the European elections, when they lost all but one of their MEPs.