North west water company United Utilities is appealing for help after sightings of an unusual-looking animal in the sewer network.
The creature, which one worker described as being 'far too big for a rat, standing upright on strong back legs' has been spotted in sewers in the north west in recent weeks.
The water company has today published CCTV footage of the creature, filmed by sewer engineers during a pipe survey, in the hope that the public can help to provide answers.
All footage can be viewed Here.
Mike Wood, United Utilities regional wastewater network manager said: "Several of our employees have reported sightings of some kind of animal. We've reviewed the CCTV footage, and it certainly doesn't look like a typical sewer rat.
"We are hoping that the public can help us. The animal could possibly be a domestic pet or feasibly, an animal which has escaped from the zoo. It seems to be feeding on fat deposits which have built up on the inside of pipes.
"We're asking the public to look at the footage, and to contact us if they can shed any light on what the creature is, and where it might have come from."
Sewer workers at the company have jokingly dubbed the creature 'Messie'.
Ian Appleton from United Utilities was operating the CCTV unit which caught the footage of the creature. He said: "We survey the sewers using hi-tech cameras mounted on small mobile vehicles - like very expensive remote control cars.
"I was sat in the van looking at the live sewer images on a monitor. I physically jumped when I saw the thing. My first reaction was, 'that's the biggest rat I've ever seen.'
"Then it stood up on two legs, and looked almost simian. I was a bit freaked out. I've been in the business 25 years, and it's the most unusual thing I've ever seen down there.
"All the lads have seen the footage now, and it gets the same reaction every time. You're just waiting for them to jump."
United Utilities is appealing to customers to post any information they have about the creature on Twitter, using #monstersightings Among the more unusual items found in north west sewers in recent years are a railway sleeper, false teeth, bullets, a motorbike, a wad of used banknotes and a live salamander.
United Utilities runs a customer-focused campaign called What Not To Flush, to encourage households not to put items down the loo or sink which can cause pipe blockages.