What a difference five years make. The morning after the previous European elections, the UK Independence Party (Ukip) was emerging as a significant force, the third-biggest British political troop in Europe.

The television chatshow host Robert Kilroy-Silk had helped propel the party to 2.7 million votes – 16 per cent of the poll. Twelve European Parliament seats (and the very mention of the party's name) provoked real fear as well as loathing among senior figures in the then-embattled Conservative Party, gripped by the prospect that Ukip could threaten their core vote.

Senior Tories shudder no longer. As Ukip prepares last-ditch defences ahead of this June's Euro elections, the party has been dogged by scandal and infighting. Mr Kilroy-Silk has long departed in acrimony and the current leader, Nigel Farage, has faced bitter recriminations over the party's direction as it enters polls that will determine whether it continues to exist as a serious political unit.

Download the new Independent Premium app Sharing the full story, not just the headlines

The party has garnered only between 1 and 2 per cent of voters' support in recent polling, although the only poll of Euro election voting intentions did put its support at 7 per cent. Its party conference in September was overshadowed by reports of plotting, intrigue and extraordinary internal feuds. In September, The Independent revealed that the party's press officer, Annabelle Fuller, had resigned after receiving phone threats. Senior Tories breathed sighs of relief as they watched the events in Bournemouth unfold.

The Ukip website boasts of the party's antics in the European Parliament last month, where MEPs sang the national anthem out of tune to disrupt their colleagues' rendition of the EU "anthem", Beethoven's "Ode to Joy". They have blamed the part-privatisation of the Royal Mail on EU directives and linked increases in the rat population to European recycling targets.

Yesterday, the former One Man and His Dog presenter Robin Page announced his resignation from the party, claiming his former colleagues were "in the process of imploding". He accused Mr Farage of despotic tendencies and obtaining "almost complete centralised power of Ukip". (Mr Farage says constitutional changes passed earlier this year were a "tidying-up operation" and accuses Mr Page of sour grapes.) Earlier this month, the economist Professor Tim Congdon quit to rejoin the Conservatives. Mr Farage has also faced attacks from two senior figures expelled from the party's national executive amid a row over reforms to its constitution, with his critics taking to the blogosphere to vent their spleens.

Meanwhile, Ukip's membership has fallen from a peak of 26,000 to about 15,000. Donations last year reached £200,000, sharply down on the £377,000 raised in 2007, although the party says it has raised hundreds of thousands of pounds this year in preparation for the June ballots.

Ukip is defending nine of the 12 seats it won in 2004. Mr Kilroy-Silk quit to form his own Veritas party, Ashley Mote was expelled after being arrested for benefit fraud, while Tom Wise was suspended after being investigated by EU anti-fraud watchdogs.

Mr Farage admitted that the June elections represent a crucial test for his party. But he insisted that Ukip could maintain or even exceed its 2004 high water mark.

He said his opponents were "middle-aged, elderly men diametrically opposed to many of the things I stand for". He added: "I think the party has changed. It is much more diverse in terms of its ethnic mix. It has been seen as a bank of angry old men from the rugby club. That situation is very different now."

The Ukip peer Lord Pearson of Rannoch, who caused a storm by inviting the right-wing Dutch MP Geert Wilders to the House of Lords to screen a controversial anti-Islam film, insisted that he supported Mr Farage but admitted the party faced internal challenges to his leadership. "I think most of the real people in the party have not got time for all this internal sniping and plotting," he said. "They spent quite a lot of time lining me up as the next leader. I think they are bonkers."

Ukip will launch its Euro election campaign next month under the slogan "Lend us your Vote", an attempt to persuade voters to abandon their traditional loyalties for the day and make the poll a referendum on the EU. Mr Farage takes comfort from a YouGov poll on European Parliament voting intentions for the Taxpayers' Alliance earlier this year, which put Ukip on 7 per cent, still far below the 16 per cent high of 2004. But a string of national polls put Ukip support at between 1 and 2 per cent – which would be enough to make it electorally significant in a handful of areas. Today Ukip must fight a revitalised Tory party challenging Labour over the economy, not the demoralised opposition of five years ago.

Labour MEPs believe Ukip will retain three of their nine seats, while senior Tories have not yet written the party off, believing that concerns over immigration and arguments about British jobs could drive some voters into their arms.

Last year's local elections showed Ukip considerably weaker than four years previously, when the poll coincided with the Euro elections: the party managed just 1.9 per cent of the poll in the London Assembly list election, compared with 8.4 per cent.

But Professor John Curtice, of Strathclyde University, believes it is too soon to write off Ukip entirely, pointing out that the jobs dispute speaks to the party's anti-EU agenda. "I am surprised that we are all assuming they will not do terribly well," he said. "The small parties are still registering in the polls. European elections are Ukip's forte."