Royal albums: The Prince of Wales's Private Souvenir: 1914 - The divide d loyalties of a young officer

"Your country needs you," was the recruitment message on the poster of the Secretary of State for War, Lord Kitchener. His private message to the Prince of Wales was somewhat different.

Prince Edward's dearest wish when he received his commission in the Grenadier Guards was to be allowed to fight alongside his contemporaries. But when his battalion was posted overseas the young prince found himself transferred to the 3rd battalion, which was to remain at home. He protested to his father, only to be told that Kitchener did not mind if the young prince was killed on the front line, but he could not risk his being captured and used as a hostage. One by one he watched the names of his friends, including that of his equerry, Major Cadogan, posted on the lists of young men killed.

His protests at being left behind won him a transfer to the staff of the British Expeditionary Force's commander in France and he spent the rest of the war as a roving morale-raiser and collector of intelligence. He lived frugally, and, though provided with a Daimler, refused to use it because "the cars of the brass hats honked infantrymen off the road" and irritated the troops. Instead he travelled around on a green army bicycle, covering hundreds of miles. His desire always was to be at the scene of the action, and he had what he described as "his closest call" when the Welsh Guards were bombarded in error by French artillery.

As a prince of the crown he could not have done more to share the ordeal of his generation, and although proud of his single mention in despatches - he later framed a letter from Churchill confirming this - he was genuinely embarrassed when he was awarded the Military Cross.

But for Edward the war was significant chiefly as the crucible in which he vastly broadened his range of human experience and honed his skills at communicating with his future subjects, from all backgrounds and countries of the British Empire. In the years after the war he put this to good use in his extensive goodwill tours of the Empire and in a growing interest in domestic politics.

In the Thirties, when unemployment reached terrible new levels, he toured working-men's clubs throughout Britain and enlisted more than 200,000 men and women in occupational schemes. He became the most popular Prince of Wales for a century. Even the Jarrow marchers, when they reached London in their protest trek to demand jobs, cheered Prince Edward when they reached the capital.

And yet there was, for Edward, an ambivalence about the war. Only the year before it began he had, at his mother's suggestion, toured Germany during his Easter and summer vacations from Oxford. "The purpose of these two trips," he later wrote, "was to improve my German and to teach me something about these vigorous people whose blood flows so strongly in my veins". He was related in one way or another to most of the Royal households that reigned in Germany in those days.

The prince had progressed from one Palast or Schloss to another, sampling the lavish if formal hospitality of his relatives. He stayed with the King and Queen of Wurttenberg, whose ample figures, he noted, "betrayed the justice they did to their four full meals a day", and then with the Grand Duke of Mecklenburg-Strelitz and finally the Duke of Saxe-Coburg and Gotha whose name the British royal family bore until George V issued a declaration in 1917 changing the dynastic name to Windsor.

Edward constantly invented plausible excuses for going to Berlin, "a gay city in those pre-war days", were he got his first taste of night life. He even had an audience with Kaiser Wilhelm II who rose to greet him from behind a great desk at which he sat, not in a chair, but on a wooden block shaped like a horse's body to which was girthed a military saddle complete with stirrups.

He developed not just an affection for his kind but eccentric relatives, but an affinity for the German people.

"Much of what I saw in Germany impressed me," he later wrote. "I admired the industry, the perseverance, the discipline, the thoroughness, and the love of the Fatherland so typical of the German people."

It was an admiration which was to draw the former king to the Nazi regime which took power after that disastrous first war. His love for Germany led him into a naive sympathy with Hitler.

In 1940 Churchill wrote: "The position of the Duke of Windsor on the Continent in recent months has been causing HM and HMG embarrassment as, though his loyalty is unimpeachable, there is always a backlash of Nazi intrigue which seeks to make trouble about him."

More recently there have been suggestions, revealed in intelligence papers released two years ago by the Public Record Office, of a plot between the Nazis and the Duke that he would be restored to his throne if a German invasion of Britain was successful.

The Duke spoke, intelligence sources reported, of how England would then become the leader of a coalition of France, Spain and Portugal, while Germany would be free to march against Russia. It was a scenario which the young prince of 1914 would have found unimaginable.