An inquiry into a Conservative MP who wrongly claimed more than �90,000 worth of expenses is being seen as a test of how tough the new Parliamentary watchdog is turning out to be.

Sir Philip Mawer has completed his probe into Windsor MP Michael Trend's claim that his mistake was caused by a "misunderstanding, honestly and genuinely held".

It is up to Philip Mawer to... demonstrate to the public that he is going to be no less vigorous than his predecessor Michael Fabricant

Mr Trend had collected an annual allowance of �20,000 that was meant to fund London accommodation for MPs from faraway constituencies.

Mr Trend drove home "most evenings".

He has since offered to return the �90,277 overpayment.

Now MPs are watching the outcome of the subsequent investigation by Sir Philip, the new Parliamentary Commissioner for Standards, to see if he is as vigorous as his predecessor Elizabeth Filkin, who controversially left her job a year ago.

Hidden light?

They are particularly interested as Sir Philip has produced only three reports in his first year, compared with Ms Filkin's 12.

Sir Philip began his inquiry into Mr Trend after he received a letter from elderly piano teacher Roy Birmingham, a Windsor constituent, complaining about the expenses claim.

The investigation is now completed and Sir Philip's report will be considered by the House of Commons standards and privileged select committee.

Ms Filkin complained of a whispering campaign against her

Tory MP Michael Fabricant said he was "not surprised" Sir Philip had had "a quiet year".

"I think that Philip Mawer was chosen particularly to be a contrast to Elizabeth Filkin," he told BBC Radio 4's Today programme.

"But now it is up to Philip Mawer to re-establish the integrity of the House of Commons, and whether he chooses to hide his light under a bushel or not, what he does need to do is demonstrate to the public that he is going to be no less vigorous than his predecessor."

Reputations

Labour MP Anne Campbell, chair of the Speaker's Advisory Panel which has been looking at tightening up the monitoring of MPs expenses, said it remained to be seen whether Sir Philip had taken too low profile an approach to his job.

"I think we all want to see Sir Philip do his job properly because all our reputations are at stake," she told Today.

"When we have a case like this, the trouble is, all politicians become tarred with the same brush."

She said her panel was trying to make MPs "more accountable", although she stressed that she did not think "abuse" of the system was widespread.

"My panel is looking at ways inwhich we can introduce checks and balances which will make it much more difficult for MPs to deliberately mislead the system or infact to just forget to do the right thing."

'Intimidation'?

But Mark Oaten, chairman of the Liberal Democrats, said the "jury is still very much out on whether MPs can regulate themselves".

"Why is it, for example, a local councillor has a district auditor running around on their affairs ... but when it comes to MPs, possibly the worst that can happen to you is you maybe sent out of the chamber for five days," he told Today.

Mr Trend will not be standing at the next election

Ms Filkin quit her job as Parliamentary Standards Commissioner last February, amid complaints that MPs tried to intimidate her and witnesses in her investigations.

She also reported that her findings against five government ministers were watered down by MPs on the select committee on Standards and Privileges.

Mr Trend, who was elected to the Commons as MP for Windsor and Maidenhead in 1992 - before its boundaries changed to Windsor in 1997 - announced last month that he will not stand at the next General Election.

In a letter, the 50-year-old MP told his local Conservative Association that he wanted to "pursue other interests at the conclusion of this Parliament" and was giving early notice of his decision in order that a successor could be chosen.