When O.V.S. Bulleid's 'Merchant Navy' class 4-6-2 appeared on the Southern Railway in 1941, it was controversial. As well as looking unlike any previous steam locomotive, it was full of innovative and untried ideas, and this during the height of the Second World War. A total of 140 such locos were built over the next ten years, 110 of which were a lighter version, the 'West Country'/'Battle of Britain' class. This is the intriguing story of these locos in their original 'air-smoothed' form.