David Cameron's neighbour, who is the head of one of Britain's largest lobbying and public relations companies, denied yesterday that his company gave money to the Conservative Party despite evidence it has handed over £45,000 since Mr Cameron became leader.
Lord Chadlington, the head of the Huntsworth Group, said his company did not give money to the Conservatives "and never has".
But Electoral Commission records reveal that the company gave £15,500 to the party in August this year and has given money every year since 2008.
A spokesman for Huntsworth admitted last night that it had given money to the party by buying tickets for Conservative events, but did not provide details of the occasions involved.
The Huntsworth group owns two lobbying companies, Quiller Consultants, which is run by the former Tory strategist and Cameron confident George Bridges, and Grayling, which lobbies on behalf of some Britain's leading companies including National Grid and BT.
The donations raise concerns that lobbying companies can "buy places" at events attended by senior politicians, which could be used to pursue the interests of their clients.
Lord Chadlington is also the president of David Cameron's constituency association, and he and his wife have personally given more than £20,000 to the local party since 2007. Last month Mr Cameron faced controversy after it emerged that he had paid £137,000 for a piece of land he bought at his constituency home from Lord Chadlington.
Lord Chadlington paid £715,000 for a house next to Mr Cameron's last November and sold the Prime Minister part of the land that came with the house – including a strip of Mr Cameron's drive and two garages.
He has never moved into the property, but due to the way the deal was structured, Lord Chadlington received nearly twice the market rate for the land so that Mr Cameron could demonstrate that he did not profit from the deal.
Downing Street said the deal had been approved by his Principal Private Secretary, Mark Bowler, and by Sue Grey, the head of propriety and ethics in the Cabinet Office.
Asked about the deal, Lord Chadlington said: "I bought a house as part of my own place in the country. I had been trying to buy the house for the 20 years I had lived there and the person who owned it died and that's all that happened."
He confirmed he had given money to Mr Cameron's constituency but that was because of his role within the party.
"I'm president of the Prime Minister's constituency. I therefore have a role in the constituency which would involve me helping in various ways locally, but that's what I do."
A spokesman for Huntsworth said: "Huntsworth and Peter Chadlington have purchased tickets and Peter Chadlington has personally bought auction prizes at political events. These include a profit element which by law has to be treated as a political donation by the party. As he is president of the West Oxford Conservative Association, he has sponsored local events. Already well known... is that he has also made contributions to individual Conservative politicians... All these have been fully disclosed in the appropriate manner."