For the difficult LNER line between Edinburgh and Aberdeen, Gresley designed the 2-8-2 express locomotive of the class P2. Being the only eight-coupled express locomotive regularly used in Britain, this allowed enough traction on heavy trains on the grades which reached up to 1.34 percent. Only six were built which got names from Scottish lore.

The first one built in 1934, No. 2001 “Cock o' the North”, got Lentz poppet valves and a double Kylchap exhaust. All others received a more conventional Walschaerts valve gear. Also the first later got this type of valve gear. The last four had a longer firebox and there were also changes in production due to problems with smoke lifting. In 1936, they got streamlined fronts.

Due to reliability issues originating from the difficult maintenance under war conditions, Thompson rebuilt all six P2 into A2/2 Pacifics in 1943 and 1944. So no P2 is preserved, but today there are two undertakings which are building a new P2 each. One will be non-streamlined and called 2007 “Prince of Wales”, while the other will be called 2001 “Cock o' the North” and be streamlined, like the original 2001 after it had been rebuilt.