WEST SHOEBURY does not feel like the site of a revolution. There are no smouldering cars or placards trodden underfoot. Seagulls wheel and squawk above a grid of bungalow-lined streets sloping down to the steel waters of the Thames estuary. But in places like this—a slightly faded suburb of Southend, an Essex resort that has known better times—the populist, right-wing UK Independence Party (UKIP) stormed to victory in the local and European elections held on May 22nd. Nigel Farage called his party’s success an “earthquake” and predicted that his “people’s army” would cause yet larger tremors in the general election next May.

The results certainly register on the Richter scale. UKIP has no MPs, but won 27.5% of the ballots in the European election and became the first minor party in over a century to lead in a national vote. It picked up 161 English council seats (having won 30 in total between 2009 and 2012). It could win a handful of parliamentary seats next year. More important, it could also take hundreds of thousands of votes from the mainstream parties, making the outcome fiendishly unpredictable.

None of the mainstreamers fared well in the recently concluded polls. The Labour Party did best numerically, but fell short of expectations (see Bagehot). The Liberal Democrats shed ten of their 11 seats in the European Parliament and 310 council seats. Ashen-faced, the party’s leader, Nick Clegg, called the results “gutting and heartbreaking”. His position improved only slightly when on May 28th it transpired that a hostile Lib Dem peer, Lord Oakeshott, had attempted to destabilise Mr Clegg so cack-handedly as to force his main rival, Vince Cable, into a show of support.

David Cameron came out best among Westminster’s leaders. Having spent months bracing the Conservative Party for a terrible result, the prime minister faced little criticism over the party’s numbers, which were poor, but no worse than expected. In the long term, however, he has most to fear from UKIP. Although it took votes from all the main parties, and increasingly worries Labour, Mr Farage’s army draws most heavily on former Conservatives. Polling by Lord Ashcroft, a Tory peer, found these provided more than half of UKIP’s votes in the European election. A YouGov poll taken on May 26th showed that 18% of those who had voted Conservative in the 2010 general election plan to back Mr Farage’s crew next year. The Tories are pulling out all the stops to keep it from taking Newark, a seat in Nottinghamshire, in a by-election on June 5th.

Moreover, UKIP is strongest in Tory-held areas—as the results in Southend show. Three of the town’s wards switched from the Conservatives to UKIP, which helped cost the party control of the council. West Shoebury was one. James Moyies, elected the ward’s councillor with 46% of the vote, thanks the seaside bungalow-dwellers. Most are retired or work locally, he explains; they are the sort of aspirational working-class folk who left east London for a better life and started voting Tory under Margaret Thatcher in the 1980s. These are UKIP’s people: older, whiter, more socially conservative than the average, and disillusioned by a political elite they consider venal and remote. Farther up the hill, by contrast, the London commuters living on leafy, sinuous crescents have stuck with the Conservatives.

The same pattern is evident in constituencies along the east coast and the Thames estuary; many, such as Thurrock, Great Yarmouth and Dover, are Tory-held marginals on Labour’s target list. The results of May 22nd suggest that the potential UKIP vote there—grey-haired, white-skinned and blue-collared—could be big enough to deny the Tories such seats; either by splitting the right and letting Labour in or perhaps even handing them to Mr Farage.

But will those who voted UKIP stick with the party? In Lord Ashcroft’s poll only 51% said they would. Even that could be optimistic: in the European election in 2009 it won 16.5% of votes, but in the words of one UKIP source “buggered off to the pub” afterwards and slumped to 3.1% in the 2010 general election. UKIP’s membership actually fell between the two votes (see chart).