Ricin immunogenic in mice, rabbits, and humans. It has completed two successful clinical trials. Ricin has been involved in a number of incidents. In 1978, the Bulgarian dissident Georgi Markov was assassinated by Bulgarian secret police who surreptitiously shot him on a London street with a modified umbrella using compressed gas to fire a tiny pellet contaminated with ricin into his leg. He died in a hospital a few days later and his body was passed to a special poison branch of the British Ministry of Defence (MOD) that discovered the pellet during an autopsy. The prime suspects were the Bulgarian
London Buses route 7 from Wormwood Scrubs were renumbered 7A. This situation remained until 3 October 1934, when the newly constituted London Passenger Transport Board instituted its own numbering system. Route 7 continued with an extension to Kew Green until 22 August 1946, when the 7A was revived from Acton to London Bridge. Route 7 was withdrawn on 19 August 1958. From 14 October 1959, the old route 7A had its suffix removed, becoming plain 7. The service ran between Acton tram depot and London Bridge station via East Acton, Ladbroke Grove, Paddington station, Edgware Road, Marble Arch, Oxford Street, Holborn station and Bank