In London, emergency responders remember the nightmare they faced during the Westminster Bridge terror attack. In Staffordshire, a newly taser-trained PC must decide whether to fire her weapon for the first time, at a machete-wielding woman.

In Wakefield, a police officer is the victim of a violent attack. Greater Manchester Police are tackling the issue of knife crime in the city. The RAF are called in to help transatlantic rowers in distress.