Steven Byers, a former transport minister, described himself as a "cab for hire" as he asked for 5,000 pounds (5,500 euros, $7,500) a day in exchange for using his influence with the government. Geoff Hoon, formerly defense minister, and Patrician Hewitt, formerly health minister, asked for 3,000 pounds.

All three deny any wrongdoing. Byers has referred himself to the parliamentary standards watchdog.

Prime Minister Gordon Brown's official spokesman condemned their alleged actions on Tuesday: "The prime minister is clear that there must be no

blurring of the line between public service and private gain."

Three other politicians, two Labour and one from the opposition Conservatives, were also filmed making similar offers. Five of those caught are due to retire from parliament at the next election, expected in May. The sixth sits in the unelected House of Lords.

The investigation was carried out for a Channel Four television documentary and the Sunday Times newspaper.

Another blow to politicians' credibility

The allegations come as the Labour Party is unexpectedly making ground against the Conservatives ahead of the election. The party leader, Prime Minister Brown, has rejected calls for an enquiry into the issue.

The credibility of British politicians has been severely damaged over the last two years by a series of scandals concerning abuse of the expenses system. The broadcaster BBC has now also revealed that members of the British parliament have been breaking parliamentary rules by accepting oversees trips from foreign governments.

mll/Reuters/AFP
Editor: Andreas Illmer