Most historians of the Second World War agree that one of the critical turning points was the

Battle of Britain, whose sixtieth anniversary falls this week. For a few days in 1940, Goering hurled the Luftwaffe against the South-east of England to soften it up for the inevitable invasion which would follow. That invasion never came, principally because the Royal Air Force won the battle for air supremacy despite inferior numbers.

Churchill immortalised the Hurricane and Spitfire pilots in his famous phrase after the

battle: ''Never in the field of human conflict has so much been owed by so many to so few.'' ''The few'' were, indeed, one of the main

causes of victory, but two Scotsmen played a critical role in the victory also. The first was Robert Watson Watt, the boffin from Brechin, who had invented radar prior to the war and developed a series of coastal radar stations which were invaluable in giving early warning of the incoming Luftwaffe raids. But the man who encouraged him to do it, and fought for the building programme for Spitfires to replace the old biplanes still in use in the 1930s, and was in charge of Fighter Command during this vital period, was another Scotsman - Air Chief Marshal Sir Hugh Dowding.

Dowding's role in the Battle of Britain was crucial, in preparation before it and strategy during it. Yet, despite the victory, within three months a group of colleagues conspired to oust him from his post, and led to the serious neglect of his importance in the years after the war. Dowding's father taught at Fettes College, and went to establish a boys' prep school in Moffat where Hugh Dowding was born in 1882. After education at Winchester on a scholarship, he joined the Army and signed up for flying lessons on credit which he gambled would be refunded if the Royal Flying Corps accepted him. They did, and when his father demanded he stop ''this ridiculous flying'', the RFC replied that it could not accept his resignation since the 1914 war had just begun.

''Stuffy'' Dowding soon rose through the ranks to command his own squadron and by 1918 was a Brigadier General. His nickname derives from his complaint to a senior officer that inexperienced pilots were being sent up to meet the enemy without adequate training. ''Don't be so stuffy, Dowding,'' came the reply.

During war service he encountered three men whose lives were later to affect his own: Keith Park, the fighter ace who became a close friend, Trafford Leigh-Mallory who was anything but a friend of Park, and William Sholto-Douglas, another ace pilot whom Dowding was ordered to put on trial by court-martial. Dowding refused, since he believed him innocent, but in a twist of fate fitting for a Greek tragedy, it was Sholto-Douglas who was to play a leading part in Dowding's downfall in 1940. All four men stayed in the RAF and Dowding rose to be Commander-in-Chief of Fighter Command. Ironically, he was due to retire when the Second World War began in 1939 and he was thrust into command.

Dowding was dour, diffident, and dogmatic, but he knew more than anyone about all aspects of aerial warfare. When Churchill ordered more Hurricanes to be sent to France in the days before the withdrawal at Dunkirk, he refused since it would have left home defences vulnerable. He built up night fighters and resisted the demands that ''Big Wings'' be made part of Fighter Command strategy. Their advocates, like fighter ace Douglas Bader, claimed they gave greater fire power, while Dowding argued they were cumbersome to assemble, to manoeuvre, and left no reserve defences. When he chose to give Park command of the front-line sector in the South-east of England and left Leigh-Mallory with the Midlands, the smouldering feud between the two men began to heat up.

Despite his regard for his pilots, he remained aloof and did not visit airfields. It rendered him open to the charge of callousness, but after the war he defended himself on the grounds that it was his concern and admiration for the pilots which led him not to interfere.

That admiration was reciprocal. The pilots were sickened to learn on November 25, 1940, Dowding had been ordered by a short telephone call to leave his desk, which he yielded with a curt ''Good morning'' to Sholto-

Douglas, who had supplanted him in a coup in which Leigh-Mallory and Bader played a part.

Churchill acquiesced, and Dowding left for the US to rally support for the war effort, before retiring from the RAF in 1942. After that, Dowding was more communicative with his pilots but in an extraordinary way - by means of a spiritualist medium with whom he was friendly and he became a believer in spiritualism prior his death in 1970.

He acquired the title Lord Dowding of Bentley Priory, but at his memorial service he was called an ''Architect of Deliverance''. Today we can see the truth of the latter description

more clearly than they could in 1940.