Despite legal posts dominating his career for all but four years, he is most prominently remembered for serving as Minister for Coordination of Defence from 1936 until 1939.

[6] A staunch Protestant, he first came to high attention when in 1927 he joined with the Home Secretary Sir William Joynson-Hicks in attacking the proposed new version of the Book of Common Prayer.

The law required Parliament to approve such revisions, normally regarded as a formality, but when the Prayer Book came before the House of Commons Inskip argued strongly against its adoption, for he felt it strayed far from the Protestant principles of the Church of England.

[11] John Gunther, who described Inskip in 1940 as "the sixty-three-year-old man of mystery", reported the "cruel story" that Prime Minister Stanley Baldwin wanted to appoint someone "'even less brilliant than himself'".

[citation needed] At the outbreak of war in 1939 he was raised to the peerage as Viscount Caldecote, of Bristol in the County of Gloucester,[15] and made Lord Chancellor, but in May 1940 he once more became Secretary of State for Dominion Affairs[citation needed] to make room for the marginalising of Sir John Simon in the new war ministry of Winston Churchill.

[citation needed] As of 21 February 2025, he remains the last Lord Chief Justice to have held a ministerial office before his appointment.

Inskip was referred to in the book Guilty Men by Michael Foot, Frank Owen and Peter Howard (writing under the pseudonym 'Cato'), published in 1940 as an attack on public figures for their failure to re-arm and their appeasement of Nazi Germany.

[17] Lord Caldecote married Lady Augusta Helen Elizabeth, daughter of David Boyle, 7th Earl of Glasgow and widow of Charles Lindsay Orr-Ewing, in 1914.