In 1924, Collett modified one of his successful 'Saint' Class locomotives (2925 St Martin) to create the first of the 'Hall' Class. Modifications included 6' driving wheels and the fitting of a cab as used on the 'Castle' Class locomotives. Production started in 1928 when 80 of the new class were built and a further 178 were ordered. In 1944, Hawksworth modified the design and built a further 70 locomotives which are known as 'Modified Halls', as originally modelled by Palitoy and completed by Replica.

The 'Halls' were mixed traffic locomotives and could be found throughout the GWR and BR(WR) network. They sometimes found themselves on express services when larger locomotives were unavailable. They were seen with various tenders including the small 3,500 gallon ones but most had the 'Castle' 4,000 gallon tenders. All but one of the class passed into BR ownership and the last of the 'Halls' was withdrawn in 1966. Ten of the original 'Halls' have been preserved, one (5972 Olton Hall) having been painted red to have the honour of playing Hogwarts Castle in the Harry Potter films.