I have relatively few political heroes, but one is Elizabeth Filkin, who briefly served as parliamentary commissioner for standards a decade ago. She was appointed to her post in the wake of a wave of notorious financial scandals, mainly involving Conservative politicians. Her job was to clean up politics.

Filkin’s mistake was to take her job description literally. She exposed an appalling pattern of bullying, arrogance and greed at the heart of Westminster. MPs were appalled.

However, instead of punishing the malefactors, they turned their fire on Filkin herself, using threats, malicious gossip and a campaign of media vilification in order to rub her out. It was an all-party effort – the Labour, Tory and Lib Dem whips offices were all gleeful participants – that soon made sure she was out of a job.

In retrospect, Elizabeth Filkin was the canary in the mine – an advance signal that British politicians were bent. Years were to pass before, thanks to the vigilance of The Daily Telegraph, voters learnt the hideous truth about the lies, thievery and moral corruption of so many MPs.

Today, history is repeating itself. Shamed by the expenses scandal, Parliament was forced to create an external body, the Independent Parliamentary Standards Authority (Ipsa), to regulate the payments. From the start, MPs bitterly resented having to submit their claims to it for authorisation, just as a decade ago they hated Filkin.

Their assault on Ipsa, which began within weeks of it starting operations in May last year, has taken place on a number of levels. First, in an echo of the vindictive campaign of character assassination aimed at Mrs Filkin, senior Ipsa personnel have been targeted. Both the chairman, Sir Ian Kennedy – a hard-working and decent man, committed to public service – and his admirable chief executive, Andrew McDonald, have been the subject of vicious attack.

In an especially shameful act, Labour’s Ann Clwyd took advantage of parliamentary privilege to accuse Ipsa’s spokesman of leaking details of MPs’ expenses to the press. Clwyd furnished no evidence of her assertion, which has been convincingly denied, and she must have known that a public official was in no position to answer back. Clwyd has never had the guts to repeat her inflammatory accusation outside the Commons.

Even worse than this flagrant abuse of privilege, however, have been the verbal assaults and bullying aimed at ordinary Ipsa staff. Within days of the opening of Parliament in May last year, MPs were being openly resentful when asked to provide evidence that they incurred expenses, and became verbally aggressive when they were not paid at once. At least one resorted to foul language, reducing the very junior official he was dealing with to tears. While there were teething problems – as with any organisation – this behaviour was unforgivable. 

Bad though they were, these venomous assaults played a relatively small part in Parliament’s campaign to discredit Ipsa. In the short time that this tiny quango has existed, it has been obliged to endure no fewer than five external reviews and audits: two from the National Audit Office, separate reviews from the Public Accounts Committee and Office of Government Commerce, and a fifth from the Committee on Members’ Expenses. The second of the NAO examinations was a so-called “value for money” audit. I have found no precedent for such an examination taking place of an organisation that had not even presented its first-year accounts.

It is obvious that something very fishy is going on. The level of attention paid to Ipsa would be appropriate – desirable, even – if it was a major government department. It is a minute quango.

Here is the truth. MPs are deeply interested in how Ipsa works because it affects them in the pocket. They passionately resent its existence, and their real ambition is revealed in a report this week by the Committee on Members’ Expenses. It is a disreputable piece of work, full of errors and inconsistencies. It claims to support independent regulation of MPs’ expenses, but close examination reveals a completely different agenda.

The committee is urging a return to flat-rate allowances, which means effectively no accountability to the taxpayer. Worse still, it demands that administration of expenses should return to the House of Commons, recreating the old Fees Office, which allowed MPs to get away with pretty well anything. These proposals are to be discussed today in a debate that has been called with suspicious speed: normally it takes ages to arrange such an event in the Commons.

Something very sad is going on here. Many backbench MPs and ministers are indeed honest and decent people, dedicated to public service. But a sizeable minority of legislators are in politics for what they can get, as the expenses scandal proved.

Today’s debate is being called at a time of unprecedented national austerity, when the average living standards of ordinary people are being sliced away at a rate unprecedented since the Second World War. As a result, there are many more profound and urgent issues, yet today Parliament is setting aside valuable time to debate the terms and conditions of just 650 fairly well-paid and middle-class people.

The paradox is that Parliament is just beginning to regain the trust of voters after the appalling abuses of recent years, with the recent intake the most public-spirited and brilliant in living memory. So I hope that readers of The Daily Telegraph will take a close look at the Members who gather today.

I daresay they will find that the Commons chamber will be fuller than usual, as public duty takes second place to private gain. This spectacle is disastrous for our politics, and now is surely the moment for the three party leaders to show leadership by bringing this sorry display of self-interest to an end.

The trouble is that David Cameron, Ed Miliband and Nick Clegg are all terrified of their own backbenches. It is worth remembering that the Prime Minister’s initial instinct was to prevent the Committee on Members’ Expenses forming at all, but changed his mind after one of his periodic maulings by the 1922 Committee. Cameron was presumably told by his Whips that one way of buying off angry backbenchers was by holding out the prospect of an improvement in the rations.

It is exactly 100 years since the decision was made to award MPs an annual stipend, then worth some £400 a year. It is still interesting today to read the debate at which the sum was agreed. The dominant assumption that informed this debate (which had been spurred by the election for the first time of Labour MPs, who lacked independent means) was that there exists a firm distinction between private interest and public duty.

The chancellor of the exchequer, David Lloyd George, summed up this mood when he told the Commons the sum was simply an allowance to cover expenses and explicitly not intended to be “a recognition of the magnitude of the service”. Sadly, this sense that the job of an MP was its own reward, measured in honour, has long since vanished. Today’s Commons debate marks a reminder of the tragic abyss which divides so many members of the political class from mainstream standards of decency and restraint.

This article was first published in The Daily Telegraph.