The Liberal Democrat leader of Richmond Council has apologised after a photograph of a child swearing appeared on his party's website.

The image was used following Serge Lourie's decision to postpone the signing of a contract to develop Twickenham Riverside. It shows a young boy sticking up two fingers, alongside the caption 'liar liar pants on fire' and accompanies an article attacking the borough's Conservative group and residents' group Richmond United Group (RUG).

It claims they have spread lies about the controversial proposals, which include allowing developer Countryside to build 32 homes on the site of the former swimming pool in return for a community river centre.

Following months of speculation about the developer's financial situation as it delayed publishing its annual accounts, Cllr Lourie last week announced the council would not sign a contract until after next May, making it a key election issue.

Cllr Lourie admitted using the image was “an unfortunate error of judgement", adding: “It was taken down as soon as we realised there was something wrong,” he said. “The picture was commercially bought. I've had three complaints about it.

“I appreciate that we shouldn't use anything like that but I stand by the article. The Conservatives and RUG have been spreading lies about the riverside and our intentions for the site. I am going to spend the next six months speaking to residents to explain correctly what is going to go on there, which is something that will be good for Twickenham that we could not achieve without the funding from a developer.”

Julie Hill, of Twickenham, lodged a complaint about the image. “It was absolutely appalling,” she said. “It was thoroughly unprofessional and the little respect I had for the Lib Dems has now gone.

“To use a child like this – it was disgusting and offensive and as far as I know, Vince Cable and Serge Lourie have to approve items before they go online.

“The article itself is appalling too – we obviously have very different ideas about what counts as 'public land'. He is sticking two fingers up, not only to the Conservative party and RUG, but also to the 10,000 people who signed the petition against their plans.”