Boris Johnson has approached Justin King, chief executive of J Sainsbury, to become his principal adviser on the London 2012 Olympics.

The Tory London mayor’s approach to the supermarket head comes after his previous adviser on the London games, David Ross, resigned from the post. The departure of Mr Ross, following his admission that he had failed to disclose using shares in four public companies as collateral for personal loans, was an embarrassment for Mr Johnson and his party.