The film shows the then Princess Elizabeth, just seven, larking about in 1933.

Egging on her sister Princess Margaret, three, is their uncle Prince Edward, Prince of Wales. He was a sympathiser towards Hitler’s Nazi Germany and became King Edward VIII.

The stunning film footage of the Queen performing a Nazi salute is today revealed by The Sun.

The astonishing clip lay hidden for eight decades. The grainy home movie is thought to have been shot in 1933 or 1934, as Hitler rose to supreme power in Germany.

The 20-second cine film reveals Edward, who once gave a Nazi salute to Hitler and claimed he was “not a bad chap”, larking around with his sister-in-law the Queen Mother and her young children in the grounds of Balmoral.

The Queen, in tartan kilt or skirt, is aged around seven while Margaret is three. The clip opens with a playful Elizabeth grabbing one of the royal corgis and pushing the dog across the lawn.

Facing the camera, she raises her arm in a Nazi salute. Margaret lifts a hand — her left, in a playful wave.

Elizabeth performs a Scottish jig then raises her right arm again, joining in with the Queen Mum as they both stand bolt upright with right arms hoisted.

Encouraged by Uncle Edward, Margaret raises her arms again before the clip ends with the Queen Mum and Edward saluting with their right arms.

Despite his real Nazi salute to Hitler, the film clip is the only pictorial record of Edward in the pose.

Experts last night hailed the footage as an incredible new historical document of huge public interest.

While there is clearly no suggestion that the Queen or Queen Mother were ever Nazi sympathisers, Edward’s links with Hitler and fascism are very well documented.

And historians believe the film could cast important new light on the Royal Family’s attitudes towards Germany in the 1930s — and the influence of Nazi-loving Edward.

Dr Karina Urbach, a top Nazi expert and member of the renowned London-based Institute of Historical Research, described the film as “remarkable”.

She said: “The video is pretty shocking. The Queen has a proud Second World War record and sense of duty to her country and no one would ever suggest she was sympathetic to Nazi Germany.

“She was a child when this film was shot, long before the atrocities of the Nazis became widely known.

“But Edward was already welcoming the regime as Prince of Wales in 1933 and remained pro-Nazi after war broke out in 1939.

“He could well be teaching the Queen and Princess Margaret how to do the salute.”

The University of London academic added: “Hitler’s movement had been growing fast since 1929 and many German relatives of the Royal Family were attracted to it.

“They could well have seen the salute on newsreels and are copying it. The film involves our monarch and is an important historical document that asks serious questions of the Royal Family.

“It is right that it is put into the public domain. It is high time the Royal Archives were open for serious research on the 1930s and the issue of Edward’s politics and their impact upon his generation within the Royal Family.”

Juliet Gardiner, former editor of History Today and a Research Fellow at the Institute of Historical Research, said: “It’s an insight into British attitudes towards Germany at that time in 1933, long before everyone really realised Hitler’s designs on Europe. It is absolutely right that the public sees it.”

The film is even more remarkable as — just seven years after it was made — George VI and Queen Elizabeth became inspirational figures of wartime defiance after visiting bombed-out Londoners during the Blitz of 1940.

NAZIS WANTED KING EDWARD AND ‘GOOD QUEEN’ WALLIS

At the time the future Queen Elizabeth, now 89, would have had no inkling of the implications of making a Nazi salute.

The original film remains under lock and key. But copies of the clip were made several years ago and one has now been handed to The Sun by a source who believes it to be of massive public interest and historical importance.

Experts last night defended the Queen’s Nazi salute as evidence of the royals playing around.

Respected military historian James Holland said: “They are all having a laugh, there are lots of smiles, so it’s all a big joke.

SILLY SALUTE, BUT QUEEN MOTHER WAS ROCK IN WWII

“I don’t think there was a child in Britain in the 1930s or 40s who has not performed a mock Nazi salute as a bit of a lark.

“It just shows the Royal Family are as human as the next man.

“It’s no secret Edward met Hitler and had right-wing sympathies. But the same cannot be said about the Queen Mother or King George VI.

“The two were completely steadfast from start to finish in their abhorrence of Nazism in their role as leaders of the free world and the fight against that tyranny.”