Nigel Farage, new leader of Britain's right-wing Reform Party and thorn in the side of the governing Conservatives, was doused with a soft drink on Tuesday in his first full day of campaigning for a seat in parliament in the July 4 election.

On Monday, Farage produced the biggest shock of the campaign by announcing he would head Reform and run in the election, a major blow to Prime Minister Rishi Sunak, whose Conservative Party trails Labour badly in surveys.

Farage is best known for helping to lead a successful campaign in 2016 for Britain to leave the European Union, and his popularity has put pressure on a succession of Conservative leaders to be tougher on immigration.

Shortly after he launched his campaign in the seat of Clacton-on-Sea, southeast England, a woman threw a large cup of soft drink over him as he left a pub, footage posted on social media showed.

He appeared unharmed as he was led away by security and later posed smiling in a video posted on X holding a McDonald's cup and joking: "My milkshake brings all the people to the rally."

Richard Tice, chairman of Reform, called the attacker a "juvenile moron", saying his party would not be intimidated and the incident would help it win hundreds of thousands more votes.

Police said they had arrested a 25-year-old woman on suspicion of assault.

Interior minister James Cleverly condemned the incident as unacceptable.

A former commodities trader who is often pictured with a cigarette and pint of beer in hand, Farage has for three decades been the figurehead of euroscepticism in Britain, and is no stranger to controversy.

Charismatic and divisive, he has in the past made comments that his opponents have called racist. During the Brexit campaign, Farage appeared in front of a poster showing lines of migrants under the slogan "Breaking Point"; last month he said Muslims did not share British values.

He was doused in milkshake in 2019 while campaigning for the Brexit Party, Reform's predecessor, in Newcastle before a European Parliament election.

Then, his attacker was ordered to pay for his suit to be cleaned after pleading guilty to common assault and criminal damage. (Reuters)