How will the security gap at Olympics be dealt with?

Details of an additional 3,500 troops expected to be provided to help with 2012 London Olympics security are set to be announced by ministers later.

UK armed forces are on stand-by to provide more troops than the 13,500 already agreed, amid fears contractor G4S may not have enough trained staff.

James Brokenshire, Minister for Crime and Security at the Home Office, explains how they hope to deal with the security gap.