The SR West Country and Battle of Britain classes, collectively known as Light Pacifics or informally as Spam Cans, are classes of air-smoothed 4-6-2 Pacific steam locomotive designed for the Southern Railway by its Chief Mechanical Engineer Oliver Bulleid. 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 those 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.