The poison umbrella: film sheds new light on infamous cold war killing

Documentary questions why prime suspect was never arrested over 1978 murder in London

It was one of the most audacious murders of the cold war: the emigre Bulgarian writer Georgi Markov was waiting for a bus by London's Waterloo Bridge when a man bumped into him with the tip of his umbrella, pushing a tiny poisoned pellet into his leg. Four days later he was dead.

A Danish TV documentary out this week sheds new light on the prime suspect in the 1978 killing, the Italian-born Bulgarian agent Francesco Gullino, known as Agent Piccadilly. It also raises a whole range of new questions about why Gullino was never arrested for the killing.