Robert Temple Armstrong, Baron Armstrong of Ilminster GCB, CVO (born 30 March 1927), son of the musician Sir Thomas Armstrong, is a British life peer and former civil servant.

In a long civil service career, Armstrong worked in several departments, including HM Treasury and the Home Office. He was knighted in 1978. From 1979 to 1987, he served as Secretary of the Cabinet under Margaret Thatcher. He was subsequently made a life peer as Baron Armstrong of Ilminster, of Ashill in the County of Somerset in 1988, and sits as a crossbencher.

He is credited with bringing the phrase "economical with the truth" into popular usage, after he used it during the Spycatcher trial in 1986.

See also

• Baron Armstrong

1927 births | Living people | Life peers | British civil servants | Old Dragons | Old Etonians | Knights Grand Cross of the Order of the Bath | Commanders of the Royal Victorian Order | People associated with the University of Hull