The writer, Clive James, once wrote that while most sequels begin where the original ended, Jaws Two began where the original blockbuster film had begun. James argued the sequel was closer to a repeat with the shark posing precisely the same threat to the same characters.

"MPs' Expenses – the Sequel" is similar to Jaws Two. The original ended last summer, with MPs paying back expenses, the former Home Secretary Jacqui Smith in particular trouble and voters seething with anger. Yesterday the sequel began with MPs paying back even more expenses, Jacqui Smith being forced to apologise to the Commons and voters fuming. The plot is familiar, even if voters cannot get enough of it.

There is a view that all the parties have suffered from this repetitive saga. Senior Conservative strategists work on the assumption that all politicians are loathed and this will be the unavoidable backdrop of the forthcoming election campaign. I am told that Gordon Brown has hopes that in the end the Conservatives will be more damaged by the expenses affair than Labour.

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I suspect the Tory strategists are being too pessimistic and Brown is clutching at straws in relation to this particular issue. Like the original, the sequel plays into an anti-politics mood that chimes neatly with David Cameron's Thatcherite tunes. Cameron's recent attacks on big government make him the only leader in the Western world who believes the reckless activity of banks was the consequence of too much government rather than too little. But while voters view MPs with a loathing disdain, it is much harder for his opponents to argue that politics as a vocation can be a force for good. No wonder Cameron links the current economic crisis with his trivial proposal to reduce the number of MPs. Subliminally the MPs' expenses scandal becomes part of his wider hostility towards government and the state.

Those Labour MPs who complain about the excessively stringent approach of their latest investigator, Sir Thomas Legg, only fuel the anti-politics mood. This is no time for rational arguments. The lynch mob wants some more lynching. Of course it is unfair for new rules to be applied retrospectively as Legg appears to have done. But this is a crisis that demands cathartic sacrifices until the voters' anger is sated. MPs should pay up and hope they can move on.

Quite a lot of them will move on by leaving politics altogether. This is the only bright light in an otherwise dark affair. There is a chance to refresh parliament at the next election and fill it with a new generation of more dynamic and talented politicians. The chance will probably be missed.

All the hyperactivity and anger around the minor issue of expenses has missed a much bigger point. Most MPs are not corrupt, but nor are they especially impressive. This is not a rotten parliament, but it is a mediocre one, as was the parliament that preceded it and the one before that. Tony Blair used to despair about the lack of talent available to him as he made appointments to his various governments. Blair was hopeless at reshuffles, but then again he had a lot to be hopeless about. His benches were not bursting with talent. Nor are those behind Cameron. There is a crisis of representation in parliament because of the quality of MPs, yet the focus is on their integrity, a red herring as it usually is in British politics.

The method by which the main parties select their candidates is a more pressing issue than whether MPs pay back past expenses. The issue becomes more urgent because there will be so many vacancies. The next parliament will be unrecognisable from the one that meets again this week. Probably the turnover will be as great as in 1997, a significant consequence of the MPs' expenses affair. Yet will the level of talent be much higher?

This is not a minor question, although it is rarely posed. We are talking about the pools of talent that will form the next government and shape the fragile futures of the opposition parties.

The main reason why the question is ignored is because it leads in awkward directions. In both the Conservative and Labour parties the selections of candidates are more democratic than they used to be. Yet the change has often benefited mediocre local figures at the expense of more talented ones. One member of a local Labour constituency party in London tells me of a recent selection process that he took part in. The winner was a councillor from the constituency who had cultivated the local membership almost as a full-time job for a couple of years.

Apparently she was the least well-qualified in terms of national potential. There were two other candidates who were far more impressive, a woman from a nearby constituency and one from another part of London, both of whom spoke without notes and were dynamic public figures who had flourished in other professions. Both would have been better MPs and yet they never stood a chance against the solid, plodding councillor who was better known in the constituency. The councillor will be heading for the Commons next year.

The Conservatives have recently opted for open primaries where a number of selected candidates make their pitch to members of the public. Arguably this is more of a test for national politics, but still a limited one. A half-decent speaker from the constituency is likely to impress superficially compared with bigger figures from afar. As the Labour member who witnessed the selection of the local councillor put it to me: "Candidates being selected are good on wheelie bins but have nothing to say about taking the G20 out of recession... at least in the past regional organisers could spot a national figure like Tony Crosland or Michael Foot and make sure they got a seat." There is a great taboo here: in selection meetings does local democracy thrive at the expense of national democracy?

I do not pretend to have the answer to this conundrum. National politicians are held in such low esteem they are in no position to bypass local procedures. Yet without more talented figures elected to parliament, national politics will struggle to find figures rising to the challenges of our times, many of them more daunting than "MPs' Expenses – The Sequel".

s.richards@independent.co.uk