Election 2015: Nigel Farage launches UKIP pledges
UKIP is the only party offering real change and has a "completely distinctive plan", its leader Nigel Farage has said.
He claimed a UK passport was in effect available to half a billion people because of the country's EU membership.
He announced the party's "pledge to Britain", which includes saying no to the EU and an extra £3bn for the NHS.
His party also wants to "control our borders", cut foreign aid spending and have no tax on the minimum wage.
At a press conference in London, Mr Farage said: "Interestingly, we have got a completely distinctive plan from the other political parties.
"We are the only party in this campaign saying Britain should have a trade relationship with Europe, but not membership of the European Union.
"Directly as a consequence of that, we are the only party in this election that is actually offering a solution to the immigration crisis."
'Not intending to fail'
The party is currently polling in the low double figures, and Mr Farage himself is contesting the South Thanet seat in Kent.
The leader said he was preparing for a "hell of a fight" and that he was "confident but certainly not complacent" about becoming an MP.
"The price of failure is that you disappear off the map - I'm not intending to fail," he told the BBC.
As he was mobbed by a scrum of journalists and photographers, Mr Farage said it would be "almost impossible" for either Labour or the Conservatives to command a majority after the election, and that he wanted people to vote for UKIP so his party could hold the balance of power.
He was also joined at the event by Mark Reckless, the former Tory MP who defected to UKIP last year, who said he believed the party could win "at least a handful" of seats after 7 May.
By Robin Brant, BBC political correspondent
UKIP has long faced the accusation that it is simply a one-man band. A Farage cult.
It's something he and the party have repeatedly dismissed. But this election is all about Nigel. UKIP's number one priority is to get him elected to Parliament.
This is his sixth and almost certainly last attempt. If he doesn't win in South Thanet he's said he'll resign as leader, leaving UKIP minus its biggest asset.
UKIP has branched out with a raft of new policies but immigration remains at the core.
A demand for a referendum on leaving the EU is top of its wish list. UKIP is targeting around 20 seats.
The very least it has to do to have a good night on 7 May is hold Clacton and Rochester and get Mr Farage elected in Kent.
Two things are certain in the coming weeks: there will be organised anti-UKIP protests on the campaign trail and elements of racism (isolated elements, the party says) will emerge from within it, again.
Speaking at the launch of the pledges, Mr Farage also said a strong showing for his party in May could boost calls for electoral reform, which in turn could make his eurosceptics a "big party in British politics".
The UKIP leader also said he was concerned about the safety of some of the party's election candidates, and he has asked the Home Office for state-funded security for himself after being repeatedly targeted by protesters.
He said: "I think this will be a rough election campaign. I'm less fearful for myself but I'm concerned about some of our other candidates both at local level... and standing in the general election.
"There is I'm afraid something of a trade union-funded hate mob out there that have decided UKIP are a series of things we are not."