Kat:- Georgi Markov is believed to have been murdered after a tiny pellet containing the toxin ricin was fired into his leg from the tip of an umbrella as he was walking across Waterloo Bridge.
Mr Markov, a communist defector who was working for the BBC World Service, was waiting at a bus stop when he felt a sharp jab in his thigh and saw a man picking up an umbrella. He developed a high temperature and died three days later in September 1978.
A post-mortem examination, conducted with the help of scientists from the Government's germ warfare centre at Porton Down, established he had been killed by a tiny pellet containing a 0.2 milligram dose of ricin.