Complaints are expected to be made today to both the police and the House of Lords authorities following yesterday's Sunday Times front page story reporting that two Labour peers were prepared to accept fees of up to £120,000 to amend laws.
The Insight investigation claimed that four peers, including two former ministers, were prepared to help undercover reporters posing as lobbyists change laws in exchange for cash.
Lords Truscott, Taylor, Moonie and Snape were the peers named as willing to take consultancy fees from the fake lobbying firm.
Sunday Times journalists posed as lobbyists acting for a Hong Kong businessman who was setting up a chain of shops in the UK and wanted an exemption from the Business Rates Supplements Bill.
The journalists approached ten Lords who already had a number of paid consultancies.
According to the Sunday Times, former BAE consultant Lord Taylor said he would talk to chief secretary to the Treasury Yvette Cooper after agreeing a one-year retainer of £120,000.
The paper reported that Truscott agreed to a fee of £72,000 and said he would work "behind the scenes". The Sunday Times said that Moonie indicated he would take a fee of £30,000 and Snape said he would charge £24,000.
The investigation, by journalists Jonathan Calvert, Claire Newell and Michael Gillard, was an echo of the 1994 "cash for questions" sting in which the Sunday Times offered 20 MPs £1,000 to ask a parliamentary question and in which two Tory MPs took the bait.
In the latest investigation a Sunday Times reporter claimed to be a Lobbyist representing Hong Kong businessman Lou Li Jian (a made up name) who wanted to set up 30 retail outlets across the UK.
Liberal Democrat home affairs spokesman Chris Huhne was set to write to the Metropolitan Police today to ask for an investigation into the Sunday Times's claims.
His party colleague Norman Baker is to approach Black Rod and the chairman of the Committee on Lords' Interests, Baroness Prashar, to ask for a parliamentary inquiry.
Baker said: "If this story is substantiated, the position of these peers is untenable and they should face an appropriate fine or consider their positions.
"This is not simply 'cash for questions', these are allegations of 'cash for legislation', which is far worse."
The House of Lords code of conduct states that peers "must never accept any financial inducement as an incentive or reward for exercising parliamentary influence".