Boris Johnson has accused a BBC London reporter of talking "f***ing bollocks" after being questioned over allegations that he was too close to News International.
Tim Donovan, the BBC London political editor, has investigated alleged efforts by the Mayor to secure sponsorship money from News International when the Metropolitan Police was investigating phone hacking.
Johnson told the BBC on Monday that it was right for him to try and secure private sponsorship for improvements to the capital.
"I don't know of any discussions going on about that but what I can tell you is I think it's right to work with the private sector to get contributions that will be for the benefit of London," he said.
"You've got to get this on their air, this is important, stuff Donovan and his f***ing bollocks," he added with a chuckle.
Last month the Mayor was overheard in a foul mouthed tirade against his bitter rival Ken Livingstone. Johnson accused Livingstone of being a "f***ing liar" after a bad tempered debate on LBC radio.
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