The Stalwart was a private venture by Alvis that was adopted and entered service with the British Army in 1966 as a general transport truck in preference to the FV-431, the load carrier variant of the FV-430 series. It was one of the same line of vehicles that included the Alvis Saracen, Saladin, and Salamander. The high mobility and amphibious capabilities were considered ideal for resupplying units in the field.