Arbuthnot served as chairman of the Defence Select Committee from 2005 to 2014,[1] before being nominated as a life peer in the Dissolution Peerages List 2015 of August 2015.

Arbuthnot contested the Cynon Valley seat, in the Labour heartland of industrial South Wales, at the 1983 general election and was defeated by Ioan Evans.

A year later in 1984, Evans died and Arbuthnot fought the resulting by-election, but he was again defeated by the Labour candidate, Ann Clwyd.

In the 1987 general election, Arbuthnot was selected to contest the safe Conservative seat of Wanstead and Woodford, as the sitting MP, Patrick Jenkin, was standing down.

Arbuthnot stated that one of his most pleasing parliamentary achievements was "organising an all-party meeting with the Prime Minister for the exoneration of the pilots of the Chinook that crashed on the Mull of Kintyre in 1994".

In Opposition, he was a member of William Hague's Shadow Cabinet as the Conservative Party's Chief Whip until the 2001 general election when he returned to the backbenches.

[11] Later that year, he was further criticised in the press for £15,000 of expenses he claimed for upkeep at his second home, including tree surgery and painting his summer house.

[15] In September 2023, he supported the £600,000 "take it or leave it" Government compensation for those wrongly convicted saying on The World Tonight on BBC Radio 4, it was "a choice", and that "for some it will be a good way of putting this behind them and getting on with their lives".