27 November 2011 Last updated at 20:25

Mayor Boris Johnson holds up ATP World Tour Final

An impromptu trip to the gents by London Mayor Boris Johnson holds up the ATP World Tour Final between Roger Federer and Jo-Wilfried Tsonga at the O2 Arena.

Federer eventually went on to retain his title in his 100th Tour final, prevailing 6-3, 6-7, 6-3 against the Frenchman .