The S14 was another big step forward in bus design by Midland Red. Chassisless construction was adopted with the strengthened body frame carrying the running units and suspension. There was extensive use of glass fibre and the weight saving permitted single rear wheels. The unladen weight was, most remarkably, just over 5 tons. Retention of the company's 8 litre engine meant a lively power/weight ratio and the buses were well suited to almost every aspect of the company's operations although, with single rear wheels, not the most comfortable! The prototype S14 entered service in 1954 and the design was in production until 1959.

No. 4255 entered service from Worcester garage on 8 April 1955. It was used for disc brake experiments and, on two occasions, its engine was fitted with experimental pistons. Immediately after recertification in March 1963 it was moved to Leamington and remained there until July 1967 when it returned to Worcestershire - this time at the small Malvern garage. By now a candidate for retirement, it moved often between Hereford and Worcester garages until early in 1968 when, surprisingly, it returned to works for overhaul. This decision was even more surprising because 4255 was one of relatively few S14s not to be converted to driver only operation. The reprieved 4255 was used as a float vehicle,and operated from Malvern, Worcester, Redditch, Kidderminster and Bromsgrove garages, finally returning to Worcester until withdrawn in November 1970. 4255 covered over half a million miles during its service life. In that time it received the rear end panels of later S14 models and a refurbished interior, sporting red seats and paintwork instead of the original brown.

The bus was purchased by a local enthusiast and, early in 1977, it passed to the Museum's predecessor society. The vehicle has been stored in recent years pending a major overhaul, most particularly of its very high mileage mechanical units. A 'quickie' repaint in 2003 has considerably improved its appearance.