999ers on the scene look back at the 7/7 attacks in London. Police are called as a volatile patient assaults two paramedics on the Isle of Wight. In Manchester, a young police dog and his handler face a man armed with a crowbar.

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.