Bulgarian dissident Georgi Markov was waiting for a bus on Waterloo Bridge in London when he felt a sudden sharp pain in his leg. He turned to see a man pick up a dropped umbrella and hurry away, offering a mumbled apology. Markov thought little of it until a small red mark and fever set in over the following days.
The umbrella had been rigged to fire a tiny pellet packed with ricin, a poison for which there was and is no antidote. Markov died four days later, on 11 September 1978, from the resulting blood poisoning, becoming one of the most infamous casualties of Cold War espionage.
His killer would not be identified for almost three decades. It was not until 2005 that leaked files named the assassin as Francesco Gullino, an agent working for the Bulgarian secret service, though he was never extradited or tried for the murder.
