Evan was born in Pembury, Kent in 1956 and attended grammar school in Tunbridge Wells. He left the Metropolitan Police after 30 years service in 2011, serving as one of the countries first Football Intelligence Officers until 1996, then transferring to West End Central, where for 15 years he worked in Soho. For several years, Evan helped run the Soho Unit, specialising in combating drug dealing in the West End. During his career he frequently ran test purchase and buy-bust operations against drug dealers, resulting in the seizure of large amounts of drugs, and the successful prosecution of large numbers of dealers, many of whom received lengthy prison sentences. After retiring from the Metropolitan police in July 2011, Evan opened 'Sweet Expectations' in Rochester, Kent, the UK's first vegetarian sweet shop. In 2016 he sold the shop business and retired, before taking up writing in January 2019.