Donald Macintyre: This is a public relations disaster on an epic scale

'Mrs Filkin did not go native, allowing her sharp edge to be blunted by the seductive establishment'

Lessons quickly learned are just as quickly discarded. The job held by Elizabeth Filkin until she made her intended resignation public on Tuesday, too many MPs appear to have forgotten, was created in 1995 at a moment when the reputation of Parliament had sunk to hitherto unplumbed depths.

In the aftermath of the cash-for-questions saga, the precious principle of self-regulation was foundering in the last-chance saloon, its capacity to check the greed and venality of a small but determined minority of legislators questioned as never before. To reinforce it and, in its own words, "to rebuild public confidence in the holders of public office", the committee set up by John Major under Lord Nolan proposed, among other things, the creation of a new office: the Parliamentary Commissioner for Standards.

By virtue of the commissioner, there would now be an independent element to regulation. But self-regulation was maintained. First, the Standards Commissioner would be appointed by a body made up exclusively of MPs (a point we'll come back to in a moment). Second, another all-MP body, the Select Committee on Standards and Privileges, would take the final decisions in cases of complaints against MPs. Besides having the right to decide on punishments, if any, the committee could choose to overturn the commissioner's findings, and, indeed, it has done so on several high-profile occasions.

Which makes the decision not only to scale down her job but to invite her to reapply for it in open competition all the more remarkable. For she wasn't judge and jury – a job held as ever by MPs – she was only the investigator. Her powers to affect the careers of MPs were therefore heavily circumscribed, though not enough, it is now clear, for the powerful and shadowy parliamentary clique that chose to humiliate her.

The new post was nevertheless a success. In January 2000, 11 months after Mrs Filkin succeeded Sir Gordon Downey, the first Standards Commissioner, the Committee on Standards in Public Life commented: "We have no doubt that the establishment of this office has made a significant contribution to the promotion of, and public confidence in, standards in the House of Commons." This judgement was delivered under the chairmanship of Lord Neill, who had by then replaced Lord Nolan. What is now becoming clear is the extent to which her tormentors still don't get that the circumstances of her departure will undermine that crucial public confidence.

Elizabeth Filkin hasn't been wholly beyond criticism. That she did not go native in the ways of the club, allowing her sharp edges to be blunted by the seductive Commons establishment, was a huge asset. Perhaps she became a little too much of a public figure for her own good. There was a balance of judgement to be made about some of the more minor cases, though Mrs Filkin has been given woefully little credit for the many complaints that she rejected at first sight.

There was a genuine difference of opinion about the extent to which she interpreted her (rather ill-defined) remit to cover the possible non-parliamentary transgressions of the MPs that she investigated. (Though television viewers spellbound by the adaptation of Trollope's The Way We Live Now would find it odd if she was not able to judge a contemporary Augustus Melmotte unfit for office.) That is hardly the point. Her critics played the woman and not the ball. These issues were matters of legitimate debate on an evolving role – provided the incumbent had the security of a second term to which she was morally entitled if she did her job fairly, honestly and efficiently. As she did.

In fact, she was better than that. It was her alleged "over-zealousness" that brought Geoffrey Robinson and Teresa Gorman to book for serious breaches in findings upheld, as indeed they had to be, by the MPs themselves. Sir Gordon Downey, also an honest man (whom the Commons authorities had wanted to stay for another term), had tried but failed in each case. Are Mrs Filkin's critics saying that it would have been better if she had failed, too? Her investigation into Keith Vaz no doubt greatly irritated the Government. But that Mr Vaz, like Mrs Gorman, obstructed the inquiry is not in doubt.

She is criticised for talking to journalists. It's entirely predictable that the Speaker, Michael Martin, should have said on Tuesday that he would "look into" her release of her devastating letter to him. In fact, she did so only after Mr Martin's own office had disclosed details from it. In her dealings with journalists she tended to be scrupulous about not disclosing details that would compromise her inquiries.

One immediate question that arises is whether the curiously cosy House of Commons commission conforms to the Nolan principle that there should be an independent element in public appointments, given that it is composed solely of MPs. Precisely this question should, and perhaps will be, investigated by the Select Committee on Public Administration, which is chaired by Tony Wright, who is one of the all too few MPs to have the courage to denounce the treatment of Mrs Filkin.

The question is whether the political classes grasp the enormity of what they have done to Mrs Filkin. The Conservatives have concentrated on her implication that ministers and officials briefed against her. Certainly, several ministers and ex-ministers, including, besides Mr Vaz, two successive Secretaries of State for Northern Ireland in Peter Mandelson and John Reid and, in a minor case, John Prescott, were among those she investigated. (In each example the committee decided against further action). It would be indefensible if members of the Government or their lieutenants had briefed against her, though hard to prove.

But on the central issue, the robustness of the regulatory regime, the Opposition has been quieter. Nor is the Government as magisterially above all this as it pretends to be. Yesterday Mr Blair was adamant that the matter should be "dealt with by the House in the proper way" and that the Commons had "absolute power" to act as it saw fit. That would be more convincing if the Government was not represented, in the person of Robin Cook, the Leader of the Commons, on the commission that forced Mrs Filkin to reapply for her job.

This is a collective public relations disaster on an epic scale. History will judge that MPs preserved the semblance of robust regulation for as long as it took to recover from the immediate crisis back in 1995 and then quietly sought to revert to the status quo ante. But it is more than that. It represents a further widening of the gap between electors and elected. That so many MPs fail to see that is the most disappointing aspect of all. They fail to see any connection between that insularity and the record fall in turnout at the election.

In a popularity contest, there is little doubt whom the public would choose between Mrs Filkin and those now crying good riddance. As Mr Wright said on Tuesday, how do they face their constituents after this?

d.macintyre@independent.co.uk