Nigel Farage has insisted Ukip is the most diverse political party and “quite reflective of what modern Britain is”.
The Ukip leader also claimed the British passport is effectively available to half a billion people due to the country’s EU membership.
Mr Farage made the remarks as he announced the party’s “pledge to Britain”, which includes saying no to the EU, controlling the country’s borders, an extra £3 billion for the NHS, cuts in foreign aid spending and no tax on the minimum wage.
Mr Farage said a strong showing for Ukip at May’s election could boost the calls for electoral reform, which in turn could make his eurosceptics a “big party in British politics”.
He said: “I’ve always thought there should be election reform but that is frankly irrelevant in the next 38 days.
“Yes, this is very hard for us because you find good Ukip support in Labour constituencies and in Conservative constituencies.
“Yes, that’s a challenge but what we have to do is to get over the line in enough seats in this General Election campaign and then you’ll see how many seats we’ve actually come second in, and you’ll realise as part of a longer-term strategy this really could become a big party in British politics.”
On his quest to become an MP in South Thanet, Mr Farage said he was facing a “hell of a fight”.
He said: “There are easier seats I could have gone for. I am confident but certainly not complacent.”
Mr Farage was mobbed by photographers, camera people and journalists as he arrived in Smith Square in central London to unveil the poster truck.
He was hidden by the media scrum for the duration of the press conference and had to fight his way into his car as he left.
Although the posters include a pledge to control the UK’s borders, the word immigration does not feature.