Stamping video: What justifies police officers using force?

A police officer has been suspended after a video showed a suspect being kicked in the head and stamped on at Manchester Airport.     The police watchdog has started an investigation into the level of force apparently used by the officer.     On this episode, Niall Paterson speaks to our north of England correspondent Shingi Mararike and to former officer and Sky News police commentator Graham Wettone about the latest challenge facing Greater Manchester Police.  Audio credit: BBC Radio Manchester Producer: Emma Rae Woodhouse Promotions producer: Jada-Kai Meosa John, Ifra Khan  Editor: Paul Stanworth