All 201 of the class passed into the London and North Eastern Railway ownership in 1923, and they were classified J21 but without any sub-classes to reflect the different backgrounds or dimensions.

Withdrawal of the class began in 1929, but proceeded relatively slowly and there were still substantial numbers in service in 1943 when the survivors were renumbered between 5025 and 5123' (with gaps).

Eighty-two surviving examples passed into British Railways (BR) ownership in 1948, and renumbered by adding 60000 to their exiting numbers.

It then languished in the station yard, with No 14 (Hawthorn Leslie) or the Diesel shunter moving it to keep the motion from seizing up on occasion.

It was announced in July 2017 that the Heritage Lottery Fund bid between the Stainmore Railway Company and the Locomotive Conservation and Learning Trust, to restore both LNER J21 65033 and an ex.