That staunch defender of London's role as financial capital of the world has sprung into action again, this time over hedge funds.
The mayor claims that proposed EU plans to force hedge funds to be more transparent and borrow less will drive firms into the arms of the US and Switzerland. For the economically-uninitiated, hedge funds were said to be a key factor in the financial meltdown which hit the banking industry.
Only last month, he took on FSA head Lord Turner over his suggestions that taxes be imposed on the financial services industry, which he described in his own inimitable way as 'crackers'. True to his Conservative roots, he has gone against prevailing opinion to defend the bonus culture in banks, if only so that he could persuade bankers to donate to charidee.
Boris Johnson has been criticised in recent months for appearing to achieve not very much at all in his first year, apart from a guest appearance in Eastenders and taking on the Americans in the ceaseless battle over embassy congestion charge debts, but at least the City can claim to be getting their money's worth from the mayor.