The first to be opened was the Watford Gap Service area on the same day as the M1 - 2nd November 1959. It was operated by Blue Boar, but did not offer full catering facilities until September 1960.
The second M1 Service area, at Newport Pagnell, opened in August 1960 and was operated by Motorway Services Ltd.
In 1963, a further five Service areas were opened, Keele, Charnock Richard and Knutsford (all on the M6), Farthing Corner (M2) and Strensham (M5).
The picture of Watford Gap Service Area is taken from
"Food on the Move (The extraordinary world of the Motorway Service Area)"
by David Lawrence and others(ISBN 0 9536980 1 1)