Nigel Farage dramatically raised the stakes in Ukip's quest for political power by vowing to resign as leader if his party fails to get any seats in the 2015 general election.

Farage made the pledge on the day he told the anti-EU party's spring conference: "This is our moment.

After speaking in Torquay of "ruthless targeting" to win seats at the general election, Farage put his own future on the line.

"I said in my speech we could get several MPs, or a good number of MPs, in Westminster in 2015 provided, and I made it absolutely clear, that would not happen unless we clear this hurdle effectively on May 22 [the local and European elections this year].

"I stand by that. This is the election Ukip has waited 20 years for."

When asked if he would stand down in the event of the party not returning any MPs to the House, he said: "I would have thought so, good lord yes. I would be out the door before you could say Jack Robinson."

Ukip's leader upped the ante after delivering a rousing speech to the party faithful in Torquay. Farage's message that Britain had become "unrecognisable" because of immigration was well received by the floor.

Farage previously admitted action was needed in order to rid it of "extremists" which threatened electoral success. Recent fiascos to hit Ukip include Godfrey Bloom, whose comments last year about "bongo bongo land" sparked derision and criticism.

Ukip had altered the public debate in Britain on issues such as immigration, Farage claimed.

He added: "We as a party have claimed back the idea that debating the European issue is not some appalling thing to do. We made the European debate respectable in this country."