The SR West Country and Battle of Britain classes, collectively known as Light Pacifics  were  designed for the Southern Railway. Incorporating a number of new developments in British steam locomotive technology, they were amongst the first British designs to use welding in the construction process, and to use steel fireboxes, which meant that components could be more easily constructed under wartime austerity and post-war economy.

Shown above the Battle of Britain class Spitfire, this is a model I could not find any surviving original pictures of this loco. Click on the picture to enlarge.

They were designed to be lighter in weight than their sister locomotives, the Merchant Navy class to permit use on a wider variety of routes, including in the south-west of England and the Kent coast. They were a mixed traffic design, being equally adept at hauling passenger and freight trains, and were used on all types of services, frequently far below their capabilities. A total of 110 locomotives were constructed between 1945 and 1950, named after West Country resorts or Royal Air Force (RAF) and other subjects associated with the Battle of Britain.