Day 321/18. Supermarine Stranraer.

The Supermarine Stranraer was a 1930s flying boat designed and built by the British Supermarine Aviation Works company principally for the Royal Air Force. It entered operations in 1937 and many were in service at the outbreak of the Second World War undertaking anti-submarine and convoy escort patrols.
This is the sole surviving aircraft in the world of the type and is in the RAF Museum in Hendon, North London.