Development of the MGB started at least as early as 1958 with the prototype known by its Abingdon codename; In structure the car was a progressive, modern design in 1962, utilizing a unitary structure, instead of the traditional body-on-frame construction used on MGA. Many components such as brakes and suspension were developments of the earlier 1955 MGA, with the B-Series engine having its origins in 1947. The lightweight design reduced manufacturing costs while adding to overall vehicle strength. Wind-up windows were standard, and a driver's compartment offered lots of legroom. A parcel shelf was fitted behind the seats.