Simon studied Law at Kings College, London University, before being called to the Bar by the Honourable Society of the Middle Temple in 1978. Until the late 1990s he worked almost exclusively in the field of criminal law, prosecuting and defending enough murderers, armed robbers, con artists and other assorted villainy to provide him with a lifetime of true crime plots. Thereafter he specialised in clinical negligence and was listed in the Legal 500 as a Tier 1 specialist in his field. He retired early from the Bar to resume his literary career which started in the 1980s with books published in the UK and the USA.
He is the father of three children of whom he is inordinately proud, none of whom read his books.