By the late 1930s a lighter version of the Grange class was urgently required for those cross-country and branch line duties forbidden to heavier locomotives.

However, after nationalization, the newly created Western Region of British Railways was authorized to build ten more of the class.

[6] Unlike the Granges of 1936 where the use of a standard design and the re-use of existing components had produced a masterpiece, the initial performance of the Manors was comparatively mediocre, exhibiting poor steaming rates and high fuel consumption.

‘Were it not for the constraints of war there is every reason to expect that Swindon would have recalled the engines for modifications’[4] It was not until after nationalisation that the Western Region of British Railways sanctioned investigation into the class' shortcomings.

This revealed that the front end of the Manor restricted both steam flow and draught on the fire, with the blastpipe being too large in relation to the size of the chimney.

The blastpipe's area was reduced by a quarter, while a new design of firebar increased the air space in the grate, allowing more efficient combustion.

The first examples were despatched to depots at Wolverhampton, Bristol, Gloucester, Shrewsbury, Westbury in Wiltshire and Neyland in South Wales.

Subsequently, the class were used over the main lines of the erstwhile Cambrian Railways, with its headquarters and works in Oswestry.

Others of the class operated in the Birmingham, Gloucester and Hereford areas while the handful stationed at Reading frequently ventured on to the Southern Region line to Guildford and Redhill.

One member of the class 7808 Cookham Manor was purchased directly from BR service for preservation by the Great Western Society.

7808 Cookham Manor was used by the Great Western Society (GWS) to haul nine vintage ex-GWR carriages on an annual outing on the main line from Didcot to Birmingham.