The creature is believed to be a cane rat, with experts believing the rodents could be breeding in London’s sewers.
Pest controllers had their work cut out when a 'monster rat' was found in a playground in London.
The creature, believed to be a giant rat, was said to be bigger than a cat or a Jack Russell.
Gas engineer Tony Smith, 46, saw the rodent, which he claimed was up to 4 feet long, while working at a block of flats in London.
The large rodent, which reportedly weighed about 25lbs, was seen in a bush next to a popular children's playground.
The average body length of an adult rat is 9 to 11 inches, with a tail of 7 to 9 inches.
Pest-control experts at Rentokil believe the rodents could be breeding below the city streets.
A spokesperson explained the average brown rat in the UK is just one foot in length, compared to the two feet rodent discovered in Hackney.
A spokesperson for the pest control company said: "As a comparison the body of your average brown rat is up to 40cm in length with a tail shorter than the head and body, and about 350g - 500g in weight.
"They prefer ground living and burrowing but sometime have been know to climb. In urban areas there is often ready access to food, water and shelter.
"The brown rat is the only species to occur in sewers in the UK."
Some have claimed the rat is not, in fact, giant but there is a perspective trick involved.
Shop owners at Ridley Road market, which has over 180 stalls selling African, Asian and Caribbean food, were keen to condemn the selling of grasscutter rats, but some said they had heard rumours of rare African cuts being sold illegally.
Nazam Ali, who has run a fruit and vegetable stall at Ridley Road Market for 15 years, says he is aware of people selling bush meat like monkey at the market.
Mr Ali, 44, said: "I think people keep it under cover. There's a demand for it, things like bush meat.
"Maybe grasscutter rats are being sold, I don't know.
"People want to eat what they had back home and it's harder to get hold of here in Britain."
The creature was found dead near to an area where children play, which backed onto a railway track near Hackney Downs, north London on Thursday.
Mr Smith asked his electrician friend James Green to hold the rat while he took a picture.
His friends have reacted to the image with a mixture of 'glee and disgust'.
Mr Smith said: "This is the largest rat I've ever seen in my entire life.
"I've got a cat and a Jack Russell and it was bigger than both of those put together.
"I'd say it was about four foot.
"We were going to stick it in the bin, but before we did we thought we had better take a picture or people won't believe it's real."
'Giant 4-foot-long monster rat' found in children's playground in London could be African species - Telegraph