After labelling said millionaire Vladimir Chernukin a “geezer”, he told reporters he would not play the game of tennis if it turned out the former Russian minister was friends with Putin. This was despite Tory HQ insisting Mr Chernukin had severed his links with the Kremlin and was not a crony.
And so it was no surprise today the London mayor changed his tune. He told LBC officials at the Foreign Office – read spies at MI6 - had now carried out their own checks and Mr Chernukin was far from being a Putin crony.
Which is good news for that game of tennis. It will now go ahead – albeit not in the immediate future.
But there is a lingering question. Should tax-payer funded resources at the Foreign Office be used to determine whether the wife of a Russian millionaire can donate money to Conservative party coffers?