The 48150 class were built for the Guest Keen Baldwins Iron & Steel Company in 1937, being an enlarged version of a design dating from 1923.

Hunslet subcontracted some of the construction to Andrew Barclay Sons & Co., W. G. Bagnall, Hudswell Clarke, Robert Stephenson and Hawthorns and the Vulcan Foundry in order to meet delivery requirements.

A number of those used on the continent are believed to have worked on light and industrial railways in France, six going to the Chemins de Fer Tunisiens in 1946.

The NCB continued to use Austerities in the 1970s and a small number remained in service until the early 1980s, notably at Bickershaw Colliery, Greater Manchester.

Some of the examples that survived the longest were those fitted with mechanical stokers and Kylpor blast pipes or Giesl ejectors to improve their performance and reduce smoke.

[3] Not all have survived intact; the boiler of RSH 7135 of 1944 was used on the replica broad gauge locomotive "Iron Duke" built at the National Railway Museum in 1985.

A former Hunslet Austerity at the Watercress Line has been rebuilt from an 0-6-0ST into a 0-6-0T Thomas the Tank Engine lookalike, and another one into Douglas, also from The Railway Series.