The 1940 flight report is up for sale at a Sotheby's auction of aeronautical items in Sussex.

It gave agreement for the air ace to return to the skies despite losing both legs in a crash in 1931.

The catalogue for the sale in Billingshurst says the report relates to a refresher course Sir Douglas took at Upavon, Wiltshire between 27 November 1939 and 7 February 1940 after having artificial legs fitted.

He logged 41.40 hours on eight different types of plane during the course and the report says he was "exceptional as a pilot".

Sir Douglas went on to fly fighter planes from RAF Tangmere near Chichester during the Battle of Britain.

It was while flying from Tangmere that he was shot down over France, taken prisoner by the Germans and sent to Colditz.

A pub in Tangmere was named The Bader Arms as a tribute to the air ace, who died in 1982.

He had joined the Royal Air Force in 1930, but was invalided out of the service in 1933 after his accident.

Readmitted to the RAF in February 1940, he was eventually promoted to wing commander, in charge of three spitfire squadrons at Tangmere.