London, AP—Two former senior British government ministers denied wrongdoing Monday after they were caught in a hidden-camera sting appearing to offer access to politicians and diplomats in return for cash.

Prime Minister David Cameron said the allegations against Jack Straw and Malcolm Rifkind were “very serious matters” that should be investigated by Parliamentary authorities.

Straw, foreign secretary under Labour Prime Minister Tony Blair, and Conservative former Foreign Secretary Rifkind were secretly filmed by reporters posing as representatives of a fictional Hong Kong-based communications agency. The reporters said they were seeking top UK politicians to join the firm’s advisory board.

Rifkind was recorded as saying he could arrange “useful access” to ambassadors, while Straw spoke of using “charm and menace” to change politicians’ minds.

The sting by Channel 4’s “Dispatches” program and the Daily Telegraph newspaper reopened a debate about political lobbying. Currently, legislators can have outside business interests as long as they declare them.

Labour Party leader Ed Miliband has called for lawmakers to be banned from serving as consultants or company directors.

Rifkind and Straw, who are still lawmakers, have referred themselves to parliament’s standards watchdog and both were suspended from their party caucuses.

Rifkind, who chairs the parliamentary committee that oversees the intelligence services, said allegations of wrongdoing were “unfounded” and defended lawmakers’ right to make money.

“If you are trying to attract people of a business or a professional background to serve in the House of Commons … it is quite unrealistic to believe they will go through their parliamentary career being able to simply accept a salary of 60,000 British pounds (92,000 US dollars),” he told the BBC.

Legislators earn a basic salary of 67,000 pounds (103,000 dollars).

Straw said his conversation related to activities he might undertake once he retires from Parliament in May. He said he had complied with the parliamentary ethics code and he had checked out the bogus firm before meeting with its purported representatives.

“My checks were not sufficient to overcome the skillful deception of the undercover reporters,” he said.