Workers on the forthcoming M25 widening project have already upset many local residents. They may, however, be facing a more dangerous opponent – a big cat.

Motorist Karen Thomas said she was stunned to see the large black feline prowling just yards from the roadside at around 3pm on Thursday afternoon.

Mrs Thomas, form Chesham Bois, was driving between junctions 18 and 19 at the time of the sighting.

She said: “I am as clear as a bell about what I saw; it was a large black cat slinking along and hugging the perimeter of a field about a quarter of the way between the junctions.

“It was about 50 feet away and was far, far bigger than any dog – about ten times bigger.

“It really was like something you’d find in a zoo, with a long, rangy back and a long tail. It definitely was not a normal cat, it looked more like a panther.”

“I didn’t feel threatened at the time but I certainly wouldn’t want to come across it if I was walking.”

Mrs Thomas reported the sighting the police and has registered it on national database tracking similar sightings.

Have you seen this or any other big cat? Let us know by commenting below.