He was elected as a member of the General Council of the Bar in 1939, and was Treasurer of Lincoln's Inn in 1979, the year he retired from the House of Commons.

Promoted to Major, he served as a legal adviser at GHQ Cairo, before becoming president of the British Military Court of Tripolitania, based in Tripoli, in 1944.

In 1968 he was one of the final three National Liberal MPs who opted to wind up the party and become a full part of the Conservatives.

He was sacked in the Night of the Long Knives in July 1962, but received the consolation of being sworn of the Privy Council.

He was appointed a Knight Commander of the Order of the British Empire (KBE) in 1964,[1] and won an RSPCA bronze medal the same year for rescuing horses and pigs from a fire hear his home.

At the invitation of Ted Heath, he chaired the Committee on Preparation of Legislation which reviewed the methods for drafting Acts of Parliament.

The Renton Report was published in 1975, recommending drafting which was more based on principles than specific details to address every possible situation.

He was a leader in the movement to preserve the traditions of the House of Lords, including lifelong membership for members of the Peerage.

According to The Washington Post in 2005, Renton maintained that "the genius of the upper house is that it includes world-renowned experts in law, science and the arts who would never run for election", and that "Democracy has its limitations."

[3] He married in 1947 Claire Cicely "Paddy" Duncan, a sister of Marjorie Grimston, Countess of Verulam.

His youngest daughter, Davina, inherited Rett syndrome which left her severely mentally and physically disabled.