Supporters of the United Kingdom Independence Party (Ukip) have been pictured burning a picture of LibDem mayoral candidate Brian Paddick, who is gay, in the Soho area of London.
In a post on Twitter, UKIP press officer Gawain Towler posted an image of them in the act - with the quip:
"@UKIPLondon2012 campaign on fire in Soho"
Soho is considered to be the centre of the gay community in the capital and the photo drew outrage from some Lib Dems.
Adrian Trett, chair of LGBT Liberal Democrats, said it was "disgraceful".
Ukip confirmed to The Huffington Post UK that the incident did take place, however a spokesman said Paddick's sexuality was not the focus of the man in the photo.
"He was burning a picture of a politician he didn't like", the spokesman said.
Ukip have since apologised to the Paddick campaign for the incident. A spokesman for Ukip the person shown in the photo is not an official party member, but a friend of one.
"It was sent to our press officer, who didn't notice the lit flame in the photo and put it up. He just saw the smiling face and put it up without thinking. The photo has now been deleted," they said.
A spokesman for Paddick told HuffPost UK: "What a bunch of idiots. They should grow up."