Nock that Gresley reprimanded Thompson for interfering in the actions of a driver on an engine which had failed in service. The biggest dispute between them was on the Gresley conjugated valve gear for 3-cylinder engines. This valve gear arrangement worked well during peacetime but experienced problems due to poor maintenance during the Second World War, giving Thompson some justification for his criticism of the design. Thompson himself described the conjugated valve gear as Gresleys only real failure, but noted that Gresley himself would not admit to any failure in his own work. Gresley's passing was very unexpected, and the LNER had no immediate successor in mind. The LNER board of directors first requested permission from the Southern Railway to approach their CME, O.V.S. Bulleid, who had been Gresley's assistant until joining the Southern four years previously. Permission was granted, but he declined the offer. J.F. Harrison, the man later largely responsible for the design of No.71000 "Duke of Gloucester", was the popular choice. However, at 42 years old, it was considered inappropriate for someone so young to take the post. The LNER board then turned to Arthur Peppercorn for the CME role, but Thompson held seniority amongst other LNER officials and used this political experience to sidestep Peppercorn and take the title of CME. Temperament According to Col. H.C.B Rogers (who in turn cites a number of the LNER Engineers, Harrison, Smedley, Spencer et al.), Thompson possessed an ill temper towards his colleagues and was notoriously difficult to deal with. The Drawing Office at Doncaster had full height panelling on the walls of the corridors, to which Thompson had full-length windows fitted, so that he could see all that was going on and what people were doing. Those who did not agree with him did not work with him for long. He possessed a strong dislike of his predecessor, and changed a lot of Gresley designs to his own ideas, many of which lacked foundation, and in a balanced environment would not have been considered acceptable. He was a quietly-spoken man, but was extremely sensitive about it, and became infamous for losing his temper should anyone ask him to repeat himself. He was largely intolerant of anyone who questioned his ideas, which seemed to be an insecurity caused by his time working under Gresley. Thompson was a regular visitor to Gresley with suggested initiatives, but was often rebuffed in