Why is Osborne obsessed with bonuses?

It is hard to work out what the bankers did to George Osborne. Perhaps he was refused an overdraft at a formative age. Whatever it was, he is taking his revenge, saying that the large British banks should only be allowed to pay trivial cash bonuses. The plan has its political attractions — focus groups tell him no punishment is too harsh for the City of London — but also three significant economic drawbacks. It is vindictive, ineffective and it fails to address the true reason for the crash.

Let us first examine this on a practical level. Cash bonuses would be outlawed, but banks would still be able to pay their staff as many millions as they want in shares (how the Treasury would feel seeing its stake in the Royal Bank of Scotland diluted, and bankers paying low capital gains tax rather than high income tax, remains unexplained).