chimney and his draughting arrangement. There was also a reversion to flat fronted cabs and cab floor out of safety concerns, similar in style to Gresley A3 and in dimension to his B1 locomotives. Electric lighting and hinged discs were fitted to the front of the locomotive. Rebuilding No. 4470 Great Northern, the very first Gresley Pacific, was chosen for this rebuilding rather than being retained for future preservation. There has been much debate on the reason for this choice. Some has blamed Thompson for letting his personal feelings towards Gresley cloud his judgement. O. S. Nock describes it as ‘the most disappointing and tactless act in his short and stormy career as CME,’ and C. J. Allen stated ‘he turned it into a machine of such hideous appearance as might well have made its designer turn in his grave.’ Simon A.C. Martin believes that Thompson lacked tact and has misread the attachment of the railwaymen to Great Northern and the selection of the locomotive was not his decision, but that of the Locomotive Running Superintendent. Such a decision would have been based on the proposed locomotive's age, total mileage to date, mileage since last shopping and overall condition. The late Richard Hardy, a draughtsman working on Great Northern stated that had the Chief Draughtsman Teddy Windle remonstrated with Thompson, Thompson would have replied that it was not his decision. As the first Gresley Pacific, Great Northern has been in service since 1922 and was being shopped at the time of the selection, hence its selection. The A1 prototype was classed both as an express passenger locomotive and as a rebuild of an existing locomotive out of expediency due to wartime austerity measures. However, very limited amount of the original locomotive were retained in the rebuilding, such as the driving wheels, parts of the rear cartazzi, the tender frames and wheels. The boiler and original frame of the Gresley A10 were put into the spares pool with the frames refurbished and reused on another locomotive. The rebuilt locomotive appeared in traffic in September 1945 in Great Eastern Railway Prussian Blue with double red lining with "NE" on the tender, likely in direct tribute to three of four major railways that made up the LNER, however no written reasoning, instruction or notice were given. The locomotive was classified A1 while the remaining sixteen locomotives of Gresley's A1 class were re-classified A10.