The first section of the motorway opened between Junction 5 ( Watford ) and Junction 18 ( Crick\/Rugby ) on 2 November 1959 together with the motorway 's two spurs , the M10 ( from Junction 7 to south of St Albans originally connecting to the A1 ) and the M45 ( from Junction 17 to the A45 and Coventry ) .
The first section of the motorway opened between Junction 5 ( Watford ) and Junction 18 ( Rugby ) .