Anti-monarchy group Republic has called for the BBC’s groundbreaking documentary about the royal family, which briefly resurfaced on the internet, to be released.

Graham Smith, Republic’s chief executive, claimed the 1969 film did not show the monarchy in a “good light” and said it was an “outrage” the programme was being “deliberately” withheld from the public.

He said Republic would be writing to the BBC’s director-general Tim Davie to set out the case for releasing the documentary.

Royal fans were able to view the entire 105-minute fly-on-the-wall documentary on YouTube for the first time since it was withdrawn from use in the early 1970s.

It was quickly removed earlier this month, but only after it was reportedly viewed thousands of times.

Mr Smith, who claimed the monarchy wanted the film to remain in the BBC archive, said: “It is clear that the royals are worried about damage to their image, which is why they’re insisting the documentary stay locked away.

“It is not the job of the BBC to protect the royals from scrutiny. No-one else would have that kind of power over the BBC.”

“This is a BBC documentary, the decision to broadcast it or make it available online is the BBC’s. To deliberately keep it away from the public is an outrage.”

He added: “Having seen the documentary I can say it doesn’t paint the royals in a good light. That’s something the public have a right to see, and people will make up their own minds about who the royals are today.”

The programme offered the first insight into the domestic life of the Windsors, showing the Queen and her family enjoying a picnic at Balmoral, where a kilted Duke of Edinburgh cooked sausages on a barbecue.

Other footage captured a bare-chested Prince of Wales waterskiing and the Queen buying a young Prince Edward an ice cream with money from her own purse, before declaring: “This disgusting gooey mess is going to be in the car, isn’t it?”

In the Swinging Sixties, the royal family was viewed as becoming increasingly remote and alien compared with most people’s everyday lives.

The documentary, shot in colour, followed the Windsors for a year and was watched by millions of people.

It was a PR drive to highlight their “ordinary” side and was the first real look at the private life of the Queen and her children.

But a few years after it was broadcast, it was locked in the BBC archives – a move believed to have been made at the request of the Queen.

Clips have been used over the years in other documentaries and as part of an exhibition for the Queen’s Diamond Jubilee, but the entire programme has not been screened since the ban.

A YouTube spokeswoman has said the video was removed due to “a copyright claim”. A source has confirmed the BBC submitted a copyright claim.

A Buckingham Palace spokeswoman declined to comment, as did a BBC spokesman.