AS with any embarrassing home movie, there was bound to be an adverse reaction when grainy footage was released of the seven-year-old Princess Elizabeth giving a Nazi salute while she was on holiday with her parents in Balmoral in the summer of 1933.

Shock horror: the future queen of Britain appeared to be an admirer of the monstrous Adolf Hitler who had only recently come to power as German chancellor. As several commentators have noted, all that was missing was the finger placed between nose and lip – once the standard way of guying Hitler and his laughable little moustache.

But look again at those images from the long lost past and a different though no less interesting story emerges. Elizabeth's mother is offering encouragement, while her sister Princess Margaret looks bored and uninterested, a response that would be par for the course in her troubled life. It’s the response of her Uncle Edward, Prince of Wales and the future King Edward VIII, that holds the eye. He is the instigator of the summertime “game” – the British Royal family is well known for its love of pranks and charades. But behind the gentle encouragement being meted out to his nieces and sister-in-law there is an uglier truth. In common with many other members of the British upper classes in the 1930s, the royal family was not immune from the allure cast by Hitler and his unsavoury gang. Most notable in this context was the Prince of Wales (David to the family) who became king in 1936 and abdicated within a year, after falling in love with the American divorcee Mrs Wallis Simpson and taking the title, Duke of Windsor.

This does not mean that the Royals were a bunch of neo-Nazis, but there are still questions awaiting answers. After becoming king in succession to his brother, George VI certainly backed the policy of appeasing Hitler and lent moral support to prime minister Neville Chamberlain by allowing him to appear with on the balcony of Buckingham Palace after the triumphant return from Munich in 1938 bearing the message “peace in our time”, having signed a non-aggression pact with Hitler.

It was a decision the king came to regret but once war broke out and London was being blitzed, he and his wife became important figureheads of resistance and defiance; both their daughters wore uniform and their son-in-law, Prince Phillip of Battenberg, the future Duke of Edinburgh, saw frontline action in a naval warship.

The trouble is that there are so many moral ambiguities in the story that the truth about the royal connection to the Nazis is still as hazy as the film footage made public last week. Following research carried out by Andrew Morton, Princess Diana’s biographer, there is no longer any doubt that the Duke of Windsor had links with the Nazis and admired Hitler even after war broke out. (By way of evidence, Morton quotes an interview with an American journalist in which the duke made the extraordinary claim that “Hitler is a very great man”.) Morton’s findings also revealed the extent to which the Nazis believed that a peace deal could be brokered with Britain using the Duke of Windsor as a conduit. He also believed that much of this evidence was destroyed after the war as a means of shielding the Royal family.

According to another eminent historian, Dr Karina Urbach of the University of London, while no-one should be surprised by what is already known there is now an urgent need for full exposure: “We should at least be able to follow the story in detail from within the Royal archives.”

Educated in Munich and Cambridge, Urbach is the author of the recently published Go-Betweens For Hitler, which traces the ways in which the Nazi leader used members of the British and German aristocracy to strengthen the diplomatic relationship between the two countries. Last week she was unstinting in her criticism of what she regards as a cover-up in the Royal archives at Windsor Castle. “This is information that should have been in the public domain 50 years ago,” she said after being asked to view the offending footage from Balmoral. “The Royal archives contain matters of state. The role of the monarch is not a purely personal matter. We no longer have the divine right of kings.”

Part of the problem is that the Royal archives exist in a limbo of their own making. Unlike state papers, they are not public records (which are open to scrutiny after 30 years or more), and they cannot be accessed by freedom of information legislation. For historians – and indeed, for everyone with an interest in how we are governed – this cannot be right as the system is both opaque and unaccountable. Dr Urbach knows this only too well having uncovered two shadowy characters who epitomise the curious flirtation between the Royals and the Nazis during the 1930s when several leading figures in Britain supported a policy of appeasing Hitler.

Both straddled the aristocratic world which bound Germany and Britain at that time, and both had impeccable establishment connections. Of the two, Charles Edward, Duke of Albany, is the more obscure. Born in 1884, he was a grandson of Queen Victoria and a first cousin of King George V, and he was educated at Eton. Sixteen years later, at the turn of the century, he inherited his uncle’s ducal title of Saxe-Coburg and Gotha, the name by which the British Royal family was known until 1917 when George V changed it to Windsor.

Young Charlie Coburg (as he was known) then went the whole hog, not only becoming a German duke but changing his name to Carl Eduard and becoming a firm favourite of the German Kaiser. In time he joined the Nazi Party and was appointed a general in the German army. It was small wonder that Hitler saw him as a key player in his attempts to curry favour with the British establishment and as Urbach discovered, Coburg was instrumental in keeping open links with King Edward VIII, so much so that as late at 1945 Hitler ordered that he was “on no account to fall into enemy hands”.

The other go-between was perhaps more obvious and certainly more exotic. Princess Stephanie von Hohenlohe was a member by marriage of the Austrian princely family of Hohenlohe-Waldenburg-Schillingsfürst and was no stranger to the espionage trade having been put under surveillance in the 1930s both by the FBI and MI5. With ample reason, she was considered to be a spy, having close links to the Nazis and being a confidante of Hitler. She is best known for her friendship with the newspaper tycoon Lord Rothermere, who not only supported appeasement but used his influence to lend backing to Sir Oswald Mosley’s notorious British Union of Fascists. (To reinforce the web of aristocratic connections with the Nazis, Mosley married his mistress, Diana Mitford, in 1936 and the ceremony took place in Berlin with Hitler a guest of honour.)

So highly did Rothermere respect von Hohenlohe that he paid her an annual retainer and encouraged her friendship with Wallis Simpson – at one stage the two women lived in the same apartment block in Bryanston Court in London. It soon paid dividends. Not only did von Hohenlohe act as an intermediary for Rothermere in his dealings with Hitler, whose work he called “great and superhuman”, but she made the preparations for the Duke of Windsor and his new wife to travel to Germany in October 1937. During the 12-day trip the couple were granted all the courtesies of an official visit and in stark contrast to their reception by the British Royal family, were treated as if they were still royalty. So strongly did Hitler feel that the Duke could remain a useful ally that in 1940 a Nazi plot was hatched to kidnap him, ludicrously codenamed Operation Willi.

None of these connections took place in isolation because the British Royal family was not the only group to engineer a relationship with the Nazis during the 1930s. After the Germans were defeated in 1945, it became clear that in the event of a Nazi victory, Hitler would have expected (but would not necessarily have received) support from a number of sympathetic organisations in Britain including the Anglo-German Fellowship established in 1936 to foster links with Nazi Germany, which contained several prominent supporters of appeasement. Many were establishment figures and the fellowship’s Scottish membership included the Duke of Hamilton, Lord Arbuthnot, the Lord Lieutenant for Kincardineshire and Sir Thomas Moore, Unionist MP for Ayr Burghs.

Similarly, The Link, another influential pro-German group, founded in 1937, had several Scots amongst its membership, as did the Right Club, a secret society which had been founded in 1939 by Captain Archibald Ramsay, Unionist MP for Peebles and South Midlothian, a well-known appeaser and anti-Semite.

Although these far-right groupings had been closed down or infiltrated by the security services before the outbreak of war, they still provoked interest and Ramsay was arrested on May 23, 1940 and interned under the provisions of Defence Regulation 18b.

In addition to these pro-fascist organisations, most of which were relatively harmless if extremely wrong-headed, the Nazis would probably have looked for support from those members of the SNP who were vociferous supporters of home rule and disapproved of the continuation of the Union. The poet and classicist Douglas Young was chairman of the Aberdeen branch at the time and as a prominent opponent of conscription, he was frequently vilified as a Nazi sympathiser. That was not the case but he did advise his colleague Roland Muirhead that Scotland should seek a separate peace if an invasion were successful and that prominent Scots should be prepared to take part in the new form of governance under Nazi rule: “The Germans will look around for aborigines to run Scotland, and it is to be wished that the eventual administration consist of people who have in the past shown themselves to care for the interests of Scotland.”

Other prominent members of the nationalist community might have been considered potential Nazi sympathisers. Amongst them were the writer Ronald Macdonald Douglas, who was briefly interred, and Arthur Donaldson, a future chair of the SNP, who argued that a case could be made for Scottish neutrality. Like Young, he also resisted the imposition of conscription, because Scots had no government democratically empowered to pass such laws. Donaldson was eventually arrested in 1941 on a trumped-up charge of plotting to establish an independent pro-Nazi Scottish government similar to the administration established by Vidkun Quisling after the fall of Norway but was released a few weeks later because the evidence was so flimsy.

Other leading Scots who flirted briefly with the idea of dealing with Nazi Germany were the poets George Campbell Hay (Deorsa Mac Iain Deorsa), a Gaelic speaker educated at Fettes College and Oxford, and Hugh MacDiarmid, the pen name of Christopher Murray Grieve, a veteran on the First World War. Writing to fellow poet Sorley MacLean (Somhairle MacGill-Eain) on June 5, 1940, MacDiarmid put forward the idea that while “the Germans are appalling enough and in the short-term view more murderously destructive, they cannot win – but the British and French bourgeoisie can, and is a far greater enemy”.

The poets were dreamers who soon changed their tune. MacDiarmid, Hay and MacLean all followed their consciences and saw war service while Young spent time in prison rather than allow himself to be conscripted but the threat posed by the Royal fellow travellers was real enough. Mosley was arrested in 1940 and the same fate might have befallen the Duke of Windsor but for his connections in high places. Throughout that period – the year of the phoney war – he maintained contact with Nazi Germany and had to be ordered by Winston Churchill to move to neutral Portugal on pain of court martial. The British prime minister was not making an idle threat: the Duke of Windsor held the honorary rank of major-general and his links with the enemy was treasonous.

Seven years earlier, the salutes in Balmoral were innocent enough but they masked intentions which were clearly questionable. If the Royal family thinks otherwise they should open their archives for wider inspection.

Trevor Royle is the Sunday Herald's diplomatic editor and a distinguished historian. His recent books include A Time Of Tyrants: Scotland And The Second World War published by Birlinn, £9.99