Speculation is rife that a picture of a giant "mutant rat" found dead near a children's playground in London might not be all as it seems.

Workers found the rodent which it is claimed was "bigger than a four-year-old boy" while they were working at a block of flats near Hackney Downs, north London on Thursday.

Gas engineer Tony Smith, 46, who spotted the rodent in a bush, said: "This is the largest rat I've ever seen in my entire life."

The picture has been the subject of much speculation on social media with some users suggesting the rat might have appeared bigger due to a forced perspective creating an optical illusion.

Even Hackney Council, the borough in which the rat was found, expressed some doubts about its reported size.

Professor Jane Hurst, who specialises in mammalian behaviour and evolution at Liverpool University, told ITV News that while there's a chance a deceptive camera angle has made the creature appear larger, it is most likely a Gambian pouched rat that was someone's pet.

"They're increasingly being kept as pets because they tame quite nicely."

"It's extremely unlikely this was not someone's pet", she added.