This is the amazing moment a whale suspected of being a Russian spy brought back a girl's phone after she dropped it in the sea. 

The white beluga, which locals named Hvaldimir, was suspected of being a spy after it appeared off the coast of Norway wearing a harness in 2019. 

An expert has now claimed it is likely the whale, which was found dead in September, did belong to the Russian military and escaped because it was a 'hooligan'. 

Dr Olga Shpak, who has worked in Russia researching marine mammals told the BBC while she believed it fled a naval base in the Arctic Circle, she doesn't think it was a spy. 

In incredible footage from a new BBC Two documentary, the tame whale can be seen approaching a boat full of adoring fans before passing a woman a phone in his mouth.

Several women can be heard shouting in disbelief: 'Is this for real? Oh my God, it's for real' as the phone broke through the water's surface.

In the clip, from Secrets of the Spy Whale, the marine mammal nicknamed Hvaldimir - combining the Norwegian word for whale, hval, and Vladimir Putin's first name - bobs his head up and down as people splash water gently around his face.

The 14ft whale then releases the phone into the hand of a girl before slowly descending back into the water with an open mouth, making it appear as if he is smiling.

Other clips of the beluga also appear in the film, showing him cheekily poking his head through the water in Hammerfest - a town in Finnmark, Norway - as people gathered to catch a glimpse of the famous aquatic agent.

Another piece of footage shows Hvaldimir retrieving what appears to be a yellow floater from the sea as he is cheered on by fans.  

Hvaldimir's body was found floating at the Risavika Bay in southern Norway in September, and at the time of death animal rights groups claimed he has been shot.

But a forensic examination carried out just a week later concluded that human activity did not directly lead to the death of the animal, which had died after a stick became lodged in its mouth.

An autopsy showed the 35cm in length and 3cm wide stick was stuck in the animal's mouth, and police said Hvaldimir had also sustained some 'completely superficial' injuries, adding 'there was no evidence suggesting that Hvaldimir was shot'.

He was first spotted by fishermen near the northern island of Ingoya in April 2019 wearing a harness and what appeared to be a mount for a small camera and a buckle marked with the text: 'Equipment St Petersburg.'  

This sparked allegations that Hvaldimir was a Russian spy, but the new BBC documentary recently claimed he may have been guarding Kremlin property.

After 10 months of investigations into the secret underwater agent, makers of Secrets of the Spy Whale, found evidence that suggested he may have been trained as a covert 'guard whale' rather than being sent out to sea to carry out maritime espionage. 

'Our latest findings about the potential role that Hvaldimir had been trained to do brings us closer to solving the mystery, but they also prompt many further questions about what Russia might be seeking to guard in the Arctic, and why,' Jennifer Shaw, director of the film told The Observer.

As Shaw and her team looked into the mystery, they met with one of the last remaining veterans of an early US Navy programme and former dolphin trainer who explained the advantages of using such creatures as guards.

Blair Irvine told the newspaper that bubbles are created from the movements of swimmers, which in turn create noise.

As a dolphin's hearing is so sensitive, it was a foolproof method to catching intruders - and the Soviet Union quickly launched its own programme using similar techniques.

A phalanx of dolphins were allegedly used to guard the Black Sea fleet in Crimea, and while kept in floating cages, they were trained to give a signal if any underwater intruders were approaching.

Shaw also revealed to the newspaper that it was clear Hvaldimir was trained in a similar way, as she had witnessed him placing his nose on anything that appeared to be a target.

This suggested to her that the beluga had shown signs of being recruited as part of a security patrol - rather than a spy.

BBC Two's Secrets of the Spy Whale is set to air tomorrow at 9pm.