The UK Independence Party has survived Robert Kilroy-Silk and his successor’s brush with death in a plane crash last May. So, where next for Britain’s most whimsical Eurosceptic enterprise?

Scarborough out of season is an empty, windy place. At the Spa Complex in the South Bay in early March, the only sign that the UK Independence Party spring conference is about to take place is a table strewn with Ukip's news­letter Bulletin from Brussels. Inside are articles by the party's stars: the leader, Nigel Farage ("Euro crisis!"), Godfrey Bloom MEP ("At the court of king kangaroo") and Gerard Batten MEP ("The EU is taking liberties - ours!").

Bloom soon arrives, a reddened and rounded man wearing a jumper of lime green and yellow checks ("Are you trying to give people epilepsy, Godfrey?" someone asks), but no one seems to know where I can find Farage. Eventually, his press officer, Gawain, calls to say that he is ensconced in the bar of the Crown Spa Hotel, celebrating. The previous day, the Ukip candidate Jane Collins had come second in the Barnsley Central by-election, beating the Tories into third place. At the Crown, the party is already under way and in the middle of it all is Farage, sprawled on a sofa.

Nigel Farage: once a boy who rummaged for treasure in the ditches of Kent, now a man who accuses the president of the European Council, Herman Van Rompuy, of having all the charisma of a "damp rag". He was born in 1964 to a stockbroker father and house­wife mother. Barely a moment of his youth passed without a "piping Farageism", as he likes to call his utterances. His professional life began as an often inebriated City trader and politics followed. He joined the executive committee of the embryonic Ukip in 1993, won a seat in the European Parliament in 1999 and became the party's leader in 2006 (and again in 2010). Other politicians treat him with "contempt", he says, and he returns the favour: David Cameron "stands four-square for nothing in particular".

In front of a crowd, in parliament or on BBC1's Question Time, Farage tends to swerve between pantomime fury and unhinged glee. In person, however, he talks earnestly about his mission for Ukip. He believes that he can turn the party into the third-largest in Britain, displacing the Liberal Democrats, by attracting disaffected Tory voters and expanding its remit.

Ukip is "not just a disgusted-of-Tunbridge-Wells, anti-EU movement", he insists. It has policies on schools (bring back grammars), defence (boost the budget by 40 per cent), multiculturalism (against - the party's 2010 manifesto promoted "uniculturalism") and political correctness (guess). Immigration remains a defining issue. Farage says that Cameron's recent speech on the subject was a "direct" attempt to encroach on Ukip territory and a way of deflecting attention from what "ought to be a massive row" over changes to the benefits system. "I don't see why anybody should be able to come in [to the UK] from Poland and be able to claim Jobseeker's Allowance from day one," he says. The BNP has also accused Cameron of stealing its ideas, but Farage shies away from the association: "We've made sure we are as far away from the BNP-type mentality as we possibly can."

An ill wind

In the months leading up to the conference, Farage was busy preparing for the local elections. (This year, Ukip fought over 1,000 council seats in England alone.) The party intends to put up "a full selection of candidates" at the 2015 general election. But however hard Farage tries to expand horizons, Ukip cannot help working itself up over Nimbyish single issues. (At one point, someone presses a DVD into my hands - Europe's Ill Wind: Wind Turbines and the Tissue of Lies.)

As we talk, Farage drinks red wine (and urges me to have some; when I agree, he says, "Thank God"). His eyes pop with enthusiasm as he explains how he has transformed the party. Ukip has been beset by inner turmoil since it was founded. Farage has been at the centre of most of the skirmishes: the power struggle with the party's first leader, Alan Sked, who has since accused Farage of racism and of failing in his duties through being drunk; the unfortunate Robert Kilroy-Silk years, when the perma-tanned television presenter flirted with the party; the secret meetings with the BNP.

“Look," he says, "I grew up with an absolute horror of life being dull . . . Everything being the same, every day. Catching the same train, standing on the platform in the same place, sitting in the same seat. I grew up with a fear that life would turn out like that. But I wouldn't have dreamed that I'd get into as many scrapes as I have. Ha! It's ridiculous. And last year was the most spectacular of all."

On the day of the 2010 general election, Farage flew in a small plane trailing a Ukip banner - a good stunt, until the plane nosedived into an airfield in Northamptonshire. He emerged from the wreckage, bloodied and stunned but not seriously injured. (In another twist, the pilot was last month found guilty of making death threats against Farage because he thought the politician was "generating PR as a result of the crash".)

“I was pretty superhuman before," Farage says. "I could work, party and not sleep and that was easy." But the days of five pints before dinner are over. After the accident, he decided he wouldn't "let little things annoy me ever again, like when you're in a car and someone cuts you off at a roundabout and you feel like winding down the window and screaming at them. It doesn't matter." He concedes that he won't be leader for too long: he is "completely skint" and wouldn't mind going back to the City to recoup his wealth. "Politics is not the route to riches . . . Funny, isn't it? The public thinks everybody in politics is making gazillions."

Later, in the balloon-filled ballroom, he whirls from table to table. The members adore him - the charisma, the loathing of political correctness, the great, booming laugh. Their mood is punctured only by the complaint that the media have paid no attention to Ukip's success in Barnsley and are only interested in the collapse of the Lib Dems. It is a common grumble among Ukip members that the press mocks and ignores them. Farage calls it "the sneer of the rich, privileged and urban".

At dinner - a hefty roast - I sit next to a conference first-timer, Howard, who is wearing a Union Jack waistcoat and, at one point, tells me in a hushed voice that "the Muslims" are "breeding like flies". (Farage's response: "I'll take you to a Labour party conference, a Lib Dem conference, a Green conference - I'll take you to any conference you like - and people will say injudicious, incorrect things over dinner.")

As coffee is served, an auction begins. On offer is a mixture of items you could only imagine existing in the context of a Ukip fundraising event: a case of port, a ride on a vintage tractor, a wine-stopper made of a bit of HMS Victory, a Wisden collection, a box of meat ("mostly beef"), a Yorkshire hamper and 40 eggs. The egg donor insists on commandeering the microphone to make a speech.

The music begins shortly after the last lot is won. "Do you like rock'n'roll?" the singer yells, before embarking on a cover version of "Sex on Fire" by Kings of Leon. A young man winces. "The older generation is not going to like this," he says. Young Independence (YI), the youth wing of the party, has got wind that a journalist is present and members flock. They are mostly men, bristling with zeal. Farage adores them. This is where the future lies, he says, and the group seems to know it, eager to distinguish itself from the older, EU-obsessed generation. They want to make Ukip more open: a party for workers, one suggests. It's a war of attrition, says another - a question of patience. The average age of Ukip members is 60. "They'll die off."

Crowd-pleaser

The next morning, the party chairman introduces Farage at the conference. He gives the usual bashful preamble for someone "who needs no introduction". You can feel the audience ratchet up the enthusiasm, fidgeting with expectation. Farage relishes public speaking: he slots in jokes, jabs his finger at the sky in fury and knows which buzzwords will provoke shouts of anger ("Strasbourg") or delight ("Barnsley").

When he mentions the Conservatives, the crowd hisses its disapproval. He remembers campaigning before the last election, when people would say to him: "Just you wait till David gets in," as though all would be miraculously solved. Then he progresses to the guaranteed crowd-pleaser: Europe. "We're not anti-Europe. I love Europe," he booms. "I've drunk more Rioja than most people alive!"

A few weeks later, on the eve of the local elections, Farage and I talk again. He has been travelling the country canvassing, for Ukip as well as for Yes to AV. He is apoplectic about how the campaign has unfolded and the squabbling between the two sides. "Peter Mandelson's comments were the final straw for me," he says. "Vote Yes just to bugger up David Cameron? I mean, please, God help us. Is our politics so base that we can't even, in the second referendum in the history of our nation, have a debate about the issues?"

No wonder young people are turned off by politics, he says. He has tried to rise above such pettiness and engage the youth vote (Farage spends much of his campaigning time in universities; more than 100 of Ukip's local candidates this year were under the age of 25). He believes that YI could carry the party into Westminster in 2015. By then, perhaps, Farage will be back in the City, cashing in. From rummaging in ditches to crashing to earth in a promotional plane, his great fear was of a dull, monotonous life. He has escaped that fate, at least.

Sophie Elmhirst is an assistant editor of the New Statesman