The oldest surviving Battle of Britain pilot, shot down in his Spitfire during the desperate struggle between the Royal Air Force and Hitler's Luftwaffe, has died aged 99, a memorial trust said Tuesday.

William Walker suffered a stroke and died in hospital on Sunday, just days before he was due to attend a special dinner for veterans of the conflict in 1940, the Battle of Britain Memorial Trust said in a statement.

He was just 27 when he survived being shot in the ankle, bailing out of his plane and clinging to a shipwreck in the English Channel during the battle, which helped turn the course of World War II.

"Flight Lieutenant William Walker was a warm, engaging and friendly man who always had a twinkle in his eye," said Richard Hunting, chairman of the Battle of Britain Memorial Trust.

"He knew how important it was that we continue to tell the story of what he and the rest of the Few did in 1940."

The Battle of Britain pitted outnumbered RAF Hurricanes and Spitfires against the Nazis' aerial might, leading Winston Churchill to say that "never in the field of human conflict was so much owed by so many to so few".

Born in 1913, Walker was commissioned into 616 Squadron on June 18, 1940, according to his biography on the trust's website. At the time he was older than many of his fellow pilots, whose average age was 20.

On August 26, 1940, his Spitfire was scrambled from its base in Kenley, east London, to help intercept a large German bomber force with a heavy fighter escort heading towards England.

During a dogfight Walker's plane was badly damaged and he parachuted out, landing on a sandbank in the English Channel with an armour-piercing bullet in his right ankle.

He held onto a wrecked ship before a fishing boat rescued him. A crowd welcomed him on shore, where an elderly woman presented him with a packet of cigarettes.

Walker kept the bullet as a souvenir.

After recovering from his wound he spent the rest of the war on anti-aircraft duties and went on to become chairman of a brewery, as well as writing books of poetry.

The Battle of Britain began on July 10, 1940, and ended on October 31 the same year. More than 2,900 British, Commonwealth and Allied airmen took part in some 600 planes -- less than half the 1,750 German aircraft involved.

Adolf Hitler had Britain in his sights after British troops were forced to evacuate Dunkirk in June 1940, but the Battle of Britain caused the German Nazi leader to abandon his plans to invade and laid the foundations for Allied victory five years later.