The animal rights organisation People for the Ethical Treatment of Animals (PETA) has accused the studio tour of "The Making of Harry Potter" of mistreating owls.

Since it opened in 2012, the Warner Bros Studio Tour in London has allowed fans to glimpse the magical world of Harry Potter and his friends, but PETA was angered when it secretly filmed the tour.

The group witnessed "distressed birds... tethered in tiny cages for hours and forced to perform tricks." They also saw handlers allowing visitors to pet the owls and make them do "demeaning" tricks.

"Confining frightened owls to tiny cages where they can only chew at their tethers in frustration goes against every message of respect and kindness that J.K. Rowling's wonderful books taught us," PETA director Mimi Bekhechi told the BBC.

PETA then called on the studio tour "to make sure that the Harry Potter tour stays magical - and not cruel - by keeping live animals out of it."

In its defense, the Warner Bros Studio Tour London told the BBC that "it is essential the welfare of the birds... is of the highest standard." So after seeing the footage, they have directed the company that owns the owls, Birds and Animals to "review this matter."

A spokeswoman for Birds and Animals said that the welfare of the birds and animals under their care is their "number one priority" so they have implemented certain standards to make sure that the birds are both healthy and stress-free.

"The owls are always given regular breaks and closely monitored by a vet. Now that we have had the opportunity to see the footage, we have instigated a review of the issues raised," the spokeswoman said: "We will take appropriate action to ensure that the birds and animals always receive the very best care."