The Duke was regarded as a failure by locomotive crews due to its poor steaming characteristics and its heavy fuel consumption.

Trials undertaken by British Railways also proved disappointing, revealing problems with the draughting of the locomotive, which caused difficulties in adhering to the timetables.

It was taken to Woodham Brothers scrap yard in Barry, Vale of Glamorgan, South Wales, but was saved from being cut up when it was purchased by a group of railway enthusiasts, who restored it to as-built condition over 13 years.

However, those proposals were rejected by the Railway Executive on the grounds that attempting to develop a new form of steam motive power was unnecessary because there were enough Standard Class 7 Britannia locomotives already available for use.

However, opportunity came out of adversity when the short-lived rebuild of the former LMS Turbomotive, 46202 Princess Anne, was destroyed in the Harrow and Wealdstone rail disaster of 1952.

[2]: 64  A gap then existed in the roster for locomotives with 8P power classification, for which there was high demand to allow the efficient operation of heavy expresses on the West Coast Main Line between London Euston and Scotland.

[1]: 188–189  However, the size of the cylinders needed to achieve the 8P power classification would mean that the locomotive was outside the British loading gauge, so a reluctant reversion to the three-cylinder layout ensued.

[2] That reluctance was born from experience with the Gresley Pacifics, in which the conjugated valve gear was difficult to maintain, due to the middle cylinder being located between the frames.

[5] It was based on Italian locomotive practice and allowed precise control of steam admission to the cylinders, as well as improving exhaust flow and boiler draughting when compared to the more conventional Walschaerts and Stephenson valve gear.

[1] A standard double chimney of the Swindon type had already been fabricated in order to cut costs and it had been installed in the smokebox, supposedly before Riddles could do anything about it.

[1] As a result, the locomotive suffered due to the choke area of both the chimney and blastpipe being much too small for the pressure created by the exhaust, which led to poor draughting.

[7]: 29 Further problems relating to the firebox of the locomotive were only discovered during its restoration, including a poorly dimensioned ashpan, and dampers that were too small, starving the fire of air when operating at speed.

[9] The fact that no effort was made to rectify the problems indicates the change in policy regarding steam locomotives, with the Modernisation Plan coming into operation just as the "Duke" entered service.

[2]: 65 Restoration began in earnest, though with many components missing, the most expensive of which being the Caprotti valve gear, it took 13 years of effort on the part of enthusiasts, with assistance in the guise of sponsorships from industry, to return the locomotive to near as-built condition.

[2] They are intended to investigate how much further the locomotive's performance can be enhanced, raising speculation about the capabilities of an entire batch of Standard class 8 "Pacifics" had history been different.