Michael Brown: If I were a sitting MP, I'd be scared

Public trust won’t be restored until most of the faces in the Commons are replaced

We shall never know whether the traditional advantage of "incumbency" would have worked in Dr Ian Gibson's favour if he had chosen to seek re-election in Norwich North as an independent.

On every measure the stunning Tory victory cannot be explained away by the pathetic excuses offered by Labour's high command. But the massive stay-at-home Labour vote, which hugely exceeded the increase in the Tory vote share, suggests that the popular personality of Dr Gibson was a major factor in the Labour wipe-out. If he had stood as an independent he might very well have won. It is more likely, however, that he would have split the vote and still ensured a Tory victory.

But any sighs of relief being heaved by MPs caught up in the expenses scandal such as the Tory Julie Kirkbride (reported to be re-considering her decision to stand down), are probably misplaced. Public trust, which might have been implicitly evident in Dr Gibson's case, is unlikely to be restored until most of the faces on all sides of the Commons benches have been replaced at the next election in 283 days time (assuming polling day is 6 May 2010). This has never been a better time for mere parliamentary candidates to stand against incumbent MPs. As David Cameron said on the BBC yesterday, "politicians are more reviled and hated than they have ever been".

By contrast, I recall with horror the utter misery of campaigning as a Tory candidate in Scunthorpe, between 1976 and 1979, against a sitting Labour MP. All formal doors of authority were closed to me. Local authorities and other public bodies – schools and hospitals – would not allow me on their premises. The British Steel Corporation, Scunthorpe's largest employer, would not allow me to visit the local steelworks which then employed 20,000 of my prospective constituents.

Even during the election campaign, the returning officer – the borough council's chief executive – treated me like dirt on the orders of the controlling Labour council. I only knew I was going to win about 20 minutes before the result when his previous contempt changed to obsequious fawning as he realised he would be dealing with me for the rest of his professional life.

Having recently spoken for the Tories in Brigg and Goole, (Lab majority 2,894) – the rump of my old constituency – I found the parliamentary candidate, Andrew Percy, riding the anti- incumbency wave of public opinion by giving public commitments to claim for barely more than a bus ticket. In my day, I would travel to London in grand style in the first-class restaurant car enjoying a taxpayer-provided full English breakfast. Assuming he is elected, Mr Percy, however, will always travel second class.

I was expected to live – beyond my means – in what my late party chairman, Major Clixby Fitzwilliams, once described to me as a house "appropriate for entertaining the local grandees". Mr Percy will probably choose a modest terraced home in Goole. New candidates in all parties will don the hair-shirt and trump the so-called "advantage of incumbency" in many contests, next May, against a sitting member. Unlike me, Mr Percy is already being feted by careerist bureaucrats who no longer treat incumbency with the slavish loyalty of yesteryear.

On the assumption that the Tories win, Mr Cameron will probably have at least 200 new members within his ranks. Only 140 or so of his existing 196 MPs will be returned – thanks to voluntary or enforced retirements. And whereas Margaret Thatcher only needed 40 extra MPs to win, Mr Cameron will need a minimum of 120 in addition to those who will replace retiring Tories. Even the depleted Labour ranks will be reinforced by new replacements for MPs in safe seats. This will result in the largest turnover of MPs since 1945.

Yesterday, it was being reported that several Labour MPs – not just those directly affected by the expenses affair – are even considering resigning between now and the general election to force yet more Norwich North style by-elections. Some are allegedly prepared to stand as independent candidates. This would directly test the extent to which incumbency is still an advantage. Frankly, I am doubtful that such threats will come to anything. An MP resigning now would forfeit the one year pay-off, which Dr Gibson has done, and which is only available to a sitting MP who stands down or is defeated at the General Election.

Meanwhile, Gordon Brown lives in a dreamworld thinking that Royal Assent to the Parliamentary Standards Bill has now restored public trust in politics. The notion that the public will now see their MPs as any more trustworthy today than they were yesterday is laughable. This legislation, emasculated since its original introduction a month ago, makes a nonsense of the Prime Minister's claim that "this is root and branch reform – Parliament will never be the same again".

Like all legislation enacted in haste, it will be superseded by events requiring further changes. In the autumn Sir Christopher Kelly's recommendations from his Committee on Standards in Public Life will be published and may well contradict several of the recent enactments. As Alan Duncan, the shadow Leader of the Commons, warned last week there is an inevitable "looming collision" between the newly created Independent Parliamentary Standards Authority and Sir Christopher's committee.

Actually, it was right that MPs rejected the attempt to interfere with parliamentary privilege – the absolute right of MPs to speak in the chamber without their words being admissible in any court proceedings. It was a disgrace that the Government was even prepared to countenance such a measure. Thankfully, this piece of stupidity was defeated by the Commons, albeit with only a majority of three. Even former cabinet ministers Margaret Beckett and John Reid recognised that this was a disgraceful infringement of Parliament's right to free speech.

No legislation, standards authority or complicated rules structure can compete with the hair-shirt of challenging candidates with public promises of personal frugality scaring the wits out of incumbents. Never has the tag "MP" been a bigger millstone around the necks of those seeking re-election.