He was just a retired plumber with a reputation for complaining, speaking out, voicing his views, and intervening. But he was also a man of remarkable courage.

Standing at the entrance of his block of flats, Harold House in Finchley Road, north London, Donald Kell, 66, saw two armed men wearing balaclava masks robbing a Brink’s-Mat security lorry parked outside the Swiss Cottage branch of Lloyds Bank. The robbers had a security guard on the ground.

Without a thought for his own safety Donald Kell acted characteristically. He waded into the robbers, hitting them right left and centre with some wooden planks he had just bought. One of the robbers, irritated by the intervention, told him to “get lost” and fired a warning shot. Mr. Kell took no notice, continuing to lash out. The robber fired again, and this time the bullet went through Mr. Kell’s chest.

The killers made their getaway with just £500 in one-pound coins. Mr. Kell was taken to hospital, where he died an hour later. The Metropolitan Police say the killing, on Wednesday, July 26th, 1989, remains a high priority on their unsolved murder list.