Garreth Williams was an employee of GCHQ who had been seconded to SIS (MI6). His was found dead at his flat in Pimlico, close to the SIS headquarters on the afternoon of 23 August 2010. His remains were found in a large red pad-locked sports bag.
Born in 1979, he had proved to be a prodigious mathematician and by the age of 13 he was studying part-time at University of Wales, Bangor. A rather shy person, he was nevertheless greatly liked by his colleagues and was a successful amateur cyclist.
The Metropolitan Police considered the circumstances of his death to be "suspicious and unexplained", prompting lurid speculation in the press about the reason for his death. The balance of opinion now appears to be that the circumstances of his death related to his private life and not his work.
The secondment of Garreth Williams to GCHQ is indicative of the increasingly close co-operation of the three UK intelligence and security agencies since 1989 - and especially since 2001. Some of the work by Williams concerned the fusion of humint and short-range sigint techniques. Technical co-operation between SIS and GCHQ goes back a long way. In the mid-1970s, Teddy Poulden, who had just retired as head on engineering at GCHQ, was taken on part-time as the first head of computing at SIS.