When historians come to judge the least edifying patronage scandal of recent years, it will not be cash for honours, which anyone with half a brain realised has been happening since time immemorial. No, they will surely settle on financial collapse for honours, the enchanting outreach programme whereby bankers were given baubles, government jobs and taskforces to chair, on the basis that extremely rich men must be right (I paraphrase slightly).

I am as shocked as the next person that extremely rich men have turned out to be wrong, and this week watched the Treasury select committee grill those four senior bankers: see-no-evil, hear-no-evil, speak-no-evil, and please-no-call-me-evil. Which did you think was the ghastliest? I thought ex-HBOS man Andy Hornby, because he was the youngest-looking one, while the others already resembled fully fossilised city gents. It's a bit like why Davros was the most disturbing Dr Who villain. You could still glimpse the humanity.

And indeed, even looking at the desk place-names in that committee room there was a poignant sense of promise cut off at the knees, when comparing plain old Andy's card with those of his co-defendants - "Lord Stevenson", "Sir Tom McKillop", "Sir Fred Goodwin".

Poor Andy has yet to get his title, and one suspects it will not be the inevitability it once was in his line of work. But what a feeder club the City has been, with Labour having given 23 bankers honours since 1997. Four of them scored life peerages, and seven were knighted. Three were made government ministers, two appointed to senior posts within Downing Street, 10 have been placed on eminent councils, seven on agencies and quangos, while just the 37 have been drafted in to head up taskforces, or sit on commissions and advisory bodies.

How errant were these knights - and how erroneous. Indeed, as we survey the wreckage of the banking system, the worry is rather less that they were given titles than that they were given responsibility in so many areas of government policy. These were not sinecures. Goodwin headed up taskforces examining both the New Deal and credit unions. Yesterday I unearthed his 2006 appearance before the Treasury committee, which praised him for opening basic bank accounts. "There seems to be coming through quite a strong strand of public accountability and social conscience rather than profit," they fawned. Sir Fred's reply? "I think they work hand in hand ..."

It would be funny if it weren't so bleeding tragic. Fred's social conscience appears to have been a demented expansionist dream that brought about the biggest losses in UK corporate history. It does rather make one wonder if his work on the New Deal and credit unions should be rehoused in a government file marked Do The Opposite Of This.

Then of course there was former HBOS chief Sir James Crosby, who had done so much to drive mortgage insanity that he was naturally charged with reviewing the ailing mortgage market. He also headed the ID cards taskforce. And let's not forget Sir Derek Wanless, assigned the even littler matter of mapping the future of the NHS. Among his conclusions were a recommendation to tax junk food (amazing how non-laissez faire these bankers are when it comes to people other than themselves), and lots of lectures about the public needing to "take responsibility" for themselves. We all have our limits, and I think being invited to consider the risks of a second portion of chips by a bloke who sat mutely on the Northern Rock audit and risk committee is probably mine.

Alas, there isn't the space to continue this roll call of banker-public intellectual hybrids. But we must just salute investment banker turned government adviser David Freud, who authored the white paper on welfare reform, and came up with the ur-justification for all bankers seeking to persuade people of their eminent suitability for these complex public roles. "I didn't know anything about welfare at all when I started," he breezed to reporters, "but that may have been an advantage ... In a funny way the solution was obvious."

Unpicking the vast and meaningful influence this lot have had over every aspect of government policy in recent years would be a Piranesian nightmare. But you'd hope we've been shocked into caution, and that getting bankers to formulate social policy will one day seem as bizarre and unthinkably embarrassing a custom of bygone times as The Black and White Minstrel Show.

Then again, don't hold out too much hope. When Gordon Brown took over as PM, his now somewhat compromised reputation for caution was mocked by one Westminster wag who said: "When a bomb goes off, you can't call Derek Wanless to set up an 18-month review." Can't you? The banking system's implosion would seem to be a matter of similar emergency, and this week we learned that Brown has only gone and called a banker, Sir David Walker, to chair a review into the way bank boards operate. If and when Sir David comes to choose his seat, let us hope he opts for Lord Walker of Cloud Cuckoo Land.

marina.hyde@theguardian.com