By Tim Montgomerie
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The BBC's Eddie Mair questioned Boris as to whether he had made up a quote while working at The Times, lied to Michael Howard and had helped a friend target another journalist with threats of violence. Mr Mair accused the Mayor of London of being a "nasty piece of work". Boris looked uncomfortable throughout and unprepared for the onslaught.
LibDemVoice's Stephen Tall blogged that some Tory MPs will be glad this morning that Cameron, rather than Mr Johnson, is their leader.
I called it car crash TV. Boris' advisors need to lock the Mayor in a room for three hours and conduct some US-style debate prep so that he can answer these questions a lot more effectively in future.
2.15pm: The full interview: