UKIP euro-skeptic leader Nigel Farage launched his party's so-called Brexit battle bus in London.

Farage rode an open-topped double-decker bus and parked up outside the European Commission's building to declare that June 23 will be Britain's 'Independence Day' if the country votes to leave the European Union in the referendum.

The bus was adorned with his face, UKIP logos and had blaring music.

"We want our borders back. We want our passports back. We want our country back and if everyone that agrees with us goes out to vote on June 23, we will make it UK Independence Day. It's upbeat, it's optimistic and we believe we are going to win," shouted Farage from the top of the purple bus.

Brandishing his British-EU passport, Farage told the throng of reporters "We want our passports back, we want our borders back."

Farage argued that the ordinary general public would be better off out of the EU, saying the bloc only serves the rich and big business.

"It is the establishment, it is the wealthy, it is the multi-nationals, it is the big banks, it is those whose lives have really done rather well in the last few years who are supporting remaining and against it is the people. Against it is the people," he told reporters.

Britons vote in an 'in/out' referendum on June 23.