Is gaffe-prone Boris being muzzled?

Now that Boris Johnson is the frontrunner to become Mayor of London in the May election, is the gaffe-prone Tory candidate being kept out of the public limelight to stop him putting his foot into it? In recent weeks Johnson has missed three campaign events, prompting speculation that his Australian campaign manager Lynton Crosby is keeping Boris on a tight leash.

In the past, Johnson has famously offended the black community with talk of "piccaninnies", Liverpudlians by accusing them of wallowing in self-pity, and the people of Papua New Guinea by linking them with "cannibalism and chief-killing".

Possibly to avoid any further such mishaps he has declined to appear as a panellist with mayoral rival Brian Paddick on Radio 4's Any Questions and cited a prior engagement when he side-stepped a mayoral hustings for Property Week. Tonight, instead of being at an event organised by Time Out magazine’s candidate, editor-at-large Michael Hodges, Johnson will be at a private dinner.

Yesterday Boris blamed a diary clash. But rivals detect the influence of Crosby, known as 'the Australian Karl Rove' for his 'under the radar campaigning'. As when he ran campaigns for the former Conservative leader Michael Howard and the ex-Australian PM John Howard, Crosby is thought to be stage-managing Johnson so he doesn't lose momentum. "It's all part of an attempt to manage Johnson's public appearances and make sure that they are only in front of friendly crowds and that he is shielded from himself," claims Hodges.

Despite the apparent muzzling, flashes of Boris's jocular personality still break through. A journalist who interviewed him for the gay magazine Attitude pressed Johnson on whether he agreed with his rival Ken Livingstone's one-time assertion that everyone is potentially bisexual. "Oh, I am a polymorphous pervert," replied Boris.