The prime minister should take the lead in championing a civil service bill if he wishes to restore trust in government, a top sleaze watchdog has said.

In an interview with ePolitix.com Sir Nigel Wicks, chairman of the Committee on Standards in Public Life, said that the introduction of legislation could be "a big step in restoring some of the public trust" that has been lost in recent years.

And his call was backed by Oliver Heald, shadow leader of the Commons, who was on Monday presenting a Civil Service Bill to parliament.

Sir Nigel said that, in general, public affairs in Britain are conducted to high levels of propriety while standards in the Commons have risen since the scandals of the mid-1990s.

"However, having said all of this it is with considerable regret that as I am coming to the end of my three years as chairman of the committee there does seem to be, despite what I say, a lack of trust in public office holders," he added.

"There is a good deal of both anecdotal and some survey evidence that trust in public institutions, public office holders has, in recent years, diminished somewhat."

The watchdog suggested that the introduction of a civil service bill to regulate the relationships between ministers, civil servants, special advisers and parliament could be one way to address public mistrust.

"I don't ask for a great thick tome, I think if it was a thick tome it would be a mistake, I don't think it should be over-prescriptive," he said.

"But if we did have a civil service bill which rested on a firm platform of consensus, I think it could be a big step in restoring some of the public trust in public institutions, particularly in central government, which by all accounts seems to have fallen away recently."

Wicks said that delays in implementing such legislation could be a result of the prime minister's failure to champion its introduction.

"You have a champion always for an education bill, you have a champion if you want an asylum bill, the home secretary, but there is no real champion for a civil service bill. And therefore there is a tendency for it to be squeezed out," he said.

"Personally I think the champion for a civil service bill should be the prime minister. I think it is the prime minister who is in overall charge of government. I think he should be the person who should champion such a bill."

His call was echoed by Oliver Heald, who urged Tony Blair to back the Civil Service Bill being presented to parliament by the Conservatives.

The Bill was drawn up by the cross-party Commons public administration select committee, which has investigated the role of special advisers in the modern civil service.

"The time is long overdue for legislation which clearly sets out the role of civil servants, special advisers and ministers and gives civil servants statutory protection against political interference," Heald told ePolitix.com.

"In the current environment, with the Hutton report due to be published soon, this Bill ensures that civil servants will be treated fairly in future and would provide a ready vehicle for any further changes deemed necessary by Lord Hutton."