He has been one of the UK’s favourite and most prominent refugees for two-thirds of a century. Now Paddington Bear – official name Paddington Brown – has been granted a British passport.

The co-producer of the latest Paddington film said the Home Office had issued the specimen document to the fictional Peruvian-born character – listing for completeness the official observation that he is, in fact, a bear.

“We wrote to the Home Office asking if we could get a replica, and they actually issued Paddington with an official passport – there’s only one of these,” Rob Silva told Radio Times.

He produced the document, complete with Paddington’s photo inside, adding: “You wouldn’t think the Home Office would have a sense of humour, but under official observations, they’ve just listed him as Bear.”

Ben Whishaw, who voices the new British subject in the film Paddington in Peru, revealed that the specimen passport was not needed during production – because he spent the whole schedule in a subterranean studio in central London.

Nor did he meet any of his co-stars. “I never met Antonio [Banderas] or Olivia [Colman] for this film, but I hope I will at some point, because I watched their performances and enjoyed them so enormously. On Paddington 2, I never saw Hugh Grant, not once,” he told Radio Times.

And he added: “I would have loved to have gone to Peru and Colombia, but I didn’t get to go. I was just in a basement in Soho the entire time.”

Asked about the secret to Paddington’s voice, Whishaw told the magazine: “I don’t like to think about that really. I have no idea what I’m doing when I do it. It’s not any different to my own voice; it’s not like I’m putting on a voice, but it is somehow different.

“Obviously, he’s saying Paddington-ish things, and then it’s just trial and error. It really comes down to the tiniest little breaths and the tiniest intonations and what works with the animation.”

While some actors claim that a lot of themselves is in the character, Whishaw admitted that he doesn’t like the marmalade that goes into making Paddington’s favourite sandwiches. “It really doesn’t agree with me at all, but I am a big Marmite lover. Marmite with Lurpak butter on toast is, to me, pretty much heaven,” he said.

In the latest film – the third in the franchise – the duffel-coated bear travels to the country of his birth to visit his Aunt Lucy. But he discovers from the guitar-playing nun who runs the home for retired bears that his aunt went missing during a scientific mission.

Olivia Colman plays the nun, while Antonio Banderas plays a swashbuckling sailor who helps them iin their quest to find her.

There were hard stares when the film-makers chose Colombia rather than Peru as the filming location for the segment. New legislation to revitalise Peru’s film industry was proposed by the rightwing lawmaker Adriana Tudela, who cited the “lack of incentives and the high number of national and local bureaucratic barriers to filming in Peru” as the main drivers behind the decision.