Humfrey was born in July 1945, son of Reverend Peter and Lilian Joan Malins. Married in 1979 to Lynda, they have one son aged 19 and a daughter aged 22.
He was educated at St Johns School, Leatherhead and Brasenose College, Oxford. Humfrey has an MA in Law and qualified as a solicitor in 1971, becoming a partner in a major Surrey firm between 1975-1988, specialising in advocacy.
A keen sportsman, he played rugby for Oxford University, Richmond in the 1972 season and was selected for the Southern Counties v New Zealand All Blacks. He is currently Captain of the House of Commons Golf Team. He is widely travelled in Europe, East and West Africa, America and the Far East.
Humfrey was a member of Mole Valley District Council between 1973-1983 and Chairman of the Housing Committee.
Between 1983 and 1992 Humfrey was Member of Parliament for Croydon North West. He was a Vice-Chairman of the Backbench Legal Committee and PPS to Home Office Ministers.
He has been an Acting Metropolitan Stipendiary Magistrate (now a Deputy District Judge) since 1991, and a Recorder of the Crown Court from 1996 onwards, sitting at Kingston, Isleworth and Reading Crown Courts.
He founded the Immigration Advisory Service, a national charity providing free legal help to those with rights of appeal under immigration law in 1993, and was Chairman of Trustees until 1996. He was awarded the CBE in Her Majesty's Honours List in 1997 for services to immigration policy and community relations.
He was elected MP for Woking in 1997, and has served as the Vice-Chairman on the Legal Committee and as a member of the Home Affairs Select Committee. From September 2001 to December 2005, he was Shadow Minister for Home Affairs.