A shocked city manager believes she has caught a ‘puma-like cat’ on camera in a Hampstead neighbour’s garden.

Nora Rothrock was in the kitchen of her Ferncroft Road home when she glanced out of the first floor window to see a metre-long beast feasting on a grey cat in her neighbour’s garden.

At first the American national thought she was looking at a fox – sometimes seen roaming the garden – but on closer inspection she realised it was anything but.

“It looked really big with a glossy coat and was not beat up. It didn’t look at all nervous. It looked up only a few times. It was bizarre. It was clearly eating a fresh kill because most of the cat was intact. It was mesmerising.”

Ms Rothrock grew up in Los Angeles and would see mountain lions on walks in the surrounding countryside. She watched for about 15 minutes whilst texting warnings to neighbour Emma Hart whose garden played host to the “puma-like” creature.

“It was like a scene from a wildlife documentary. It was huge. It was a big animal. To see that in London is weird,” said Ms Rothrock who speculated it could be the same animal spotted in St Albans over the summer.

The managing director said in minutes of her spotting it the beast had “devoured” its prey.

According to the city worker, who has seen big cats in Africa, the animal was almost as big as a German shepherd though not as big as a Great Dane, it looked well fed, was fairly young and in good shape.

“It had clearly not been in any fights. You just don’t expect to see a wild animal in the middle of one of the busiest cities in the world,” she said.

Ms Rothrock, who has lived in Hampstead for 10 years, photographed the animal through her kitchen window on Monday evening, but admitted the picture quality is not the best.

When asked whether the beast could have been mistaken for a large domestic cat eating a pigeon she said: “I should have taken more photos. It was eating an adult cat. Hampstead is not where you see wildlife like that. I’m wondering now whether or not to take the rubbish out at night. I don’t have puma-fighting techniques,” she said.

By the morning the beast had moved on leaving none of its dinner’s remains.

A London Zoo spokesman confirmed there have been no escapes.

The Natural History Museum is working to identify the animal.