Labour leader Ed Miliband today demanded a Commons statement from ministers over a new lobbying row.
He intervened after a leading lobbying company was secretly taped allegedly claiming to be able to directly influence David Cameron and other senior government figures.
An executive from public affairs firm Bell Pottinger reportedly boasted to undercover reporters about the firm's access to the Prime Minister, Chancellor George Osborne and Mr Cameron's policy chief Steve Hilton.
The claims were dismissed by Downing Street sources as "outrageous" and "a load of rubbish", but Labour said they were "very serious allegations" that demonstrated the need for lobbying reform.
A spokesman for Mr Miliband tweeted: "Ministers must make Commons statement on serious lobbying allegations. Powerful should not be able to buy influence with PM."
Tim Collins, managing director of Bell Pottinger Public Affairs, allegedly claimed that Bell Pottinger had got Mr Cameron to raise the matter of copyright infringement with Chinese premier Wen Jiabao on behalf of engineering firm Dyson. He reportedly claimed: "He (the Prime Minister) was doing it because we asked him to do it."
A Downing Street spokeswoman said: "[Neither] Bell Pottinger nor any other lobbying firm has any say or influence over government policy."
A spokesman for Dyson added: "We do occasionally work with Bell Pottinger but our main conduit to the Government is via its Business Advisory Group, of which James Dyson is a member."
Mr Collins allegedly told the reporters from the Bureau of Investigative Journalism, whose investigation is published in the Independent, that he had worked with Mr Cameron and Mr Osborne in the Tory Party's research department.
"I've been working with people like Steve Hilton, David Cameron, George Osborne for 20 years-plus. There is not a problem getting the messages through," he was quoted saying.
Lord Bell, head of Bell Pottinger, today complained to the Press Complaints Commission.
He said: "As a great supporter of a free press and self-regulation, I'm most disappointed that the Independent should behave like this."
