He served as Conservative Member of Parliament (MP) for North Norfolk from 1997 until the 2001 general election, when he lost his seat to Norman Lamb of the Liberal Democrats by 483 votes.

The son of Conservative politician James Prior, he was educated at Charterhouse School and Pembroke College, Cambridge,[2] where he gained an exhibition and MA degree in Law.

He was elected as MP for North Norfolk in 1997[3] and he became Chief Executive of the Conservative Party[2] and its deputy chairman and a member of the trade and industry select committee.

He was cleared of involvement in the alleged fraud on 15 February 2007 and subsequently reappointed as chairman of the Norfolk and Norwich University Hospital NHS Trust.

[9] In April 2014 he had a hip replacement operation paid for by private insurance but was treated in a public ward at the Norfolk and Norwich University Hospital NHS Trust.

[12] In October 2016, Prior said the result of the 2016 United Kingdom European Union membership referendum was "a terrible mistake".

[15] On 5 September 2018, he was invited to attend a pre-appointment hearing with the Health Select Committee prior to being appointed Chair of NHS England,[16] succeeding Sir Malcolm Grant.