Cabinet Office minister Francis Maude has said that a statutory register of lobbyists, as Deputy Prime Minister Nick Clegg has called for, would have made "no difference at all" to recent allegations of lobbying.
"There are already rules which say that MPs cannot take money as an advocate in Parliament," he told Daybreak.
He added that the former Conservative MP Patrick Mercer's alleged offence was "against the rules," but that there was a "perfectly proper need" for professional lobbyists.
The Government will bring forward a bill to introduce a statutory register of lobbyists before Parliament's summer recess in July.
The hastily announced Government bill to create a statutory register of lobbyists is a highly politicised piece of legislation.