Over the years his clients included Jeremy Thorpe, Princess Michael of Kent, actress Maria Aitken, the Foreign Office clerk Sarah Tisdall, former member of parliament Harvey Proctor, the Queen's bodyguard Commander Michael Trestrail, the family of the Italian banker Roberto Calvi and musician Adam "Ad-Rock" Horowitz from the Beastie Boys.

On his return from the War he resumed practice as a solicitor and married his fiancée, Leah Rose Saturley, two years his junior.

Napley ran unsuccessful parliamentary campaigns as Conservative candidate in 1951 (Rowley Regis and Tipton) and 1955 (Gloucester).

Partly as a result of Napley's reputation and wide-ranging influence, the Criminal Cases Review Commission was eventually established 14 years later.

Napley also played a leading part in the formation of the British Academy of Forensic Sciences, which supports research into miscarriages of justice.

In 1981, Napley reacted angrily to questions in Parliament because his client,[4] Sir Peter Hayman was not being prosecuted despite having exchanged photos of children through the post.

[5]This assertion, whereby the more famous the accused, the less likely they would be prosecuted for any offence, including child abuse offences, due to the steep loss of reputation they would suffer as a result, was questioned by the parliamentary journalist Ronald Butt as the corruption of the rule of law, and a "two tier system" as to who was subject to the law.

However, in June 1978 Napley telephoned Carman to tell him that the former leader of the Liberal Party (UK), Jeremy Thorpe, was probably going to be committed for trial on charges of conspiracy to murder and that he was going to retain him.