London mayoral election: Boris Johnson on PM's support
1 May 2012 Last updated at 14:02 BST
Boris Johnson said he was a mayor "who tries his absolute best to unite" when asked why his manifesto made few positive references to black people in the capital.
The Conservative candidate said there were more black and minority officers in the Metropolitan Police than at any time.
He was also asked if the prime minister was a vote winner for his campaign, and how he was affected by the national polling of his party.