TWO big cats have been caught on thermal imaging cameras stalking deer in a British forest, a Government agency confirmed last night.

Under a Freedom of Information Act request, the Forestry Commission confirmed that two ‘‘reliable’’ sightings of large cats have taken place in the last seven years.

Experts monitoring deer using thermal imaging cameras spotted the animals on two separate occasions in different parts of the Forest of Dean, Gloucestershire.

Commission spokesman Stuart Burgess said the sightings had been confirmed by ‘‘very experienced’’ rangers unlikely to mistake deer for big cats.

He said today: ‘‘Both were observed in low light, using heat-activated vision equipment while they were carrying out a deer census. The colour of the animals couldn’t be made out, but these are very experienced guys and they know what is and what isn’t a deer. One definitely believed that what he saw was some sort of large cat.’’ The first sighting was at the outskirts of Churchill enclosure, east of Parkend in February 2002. The second was on the southern slopes of Staple Edge in March 2005.

Deputy surveyor Rob Guest, who was present at both sightings, said that his team were ‘‘interested, excited, and surprised’’ when the unmistakable thermal images appeared in the gloom.

He said: ‘‘I couldn’t tell you how big they were or what they were. They were just large, full cats.

‘‘At that time, going back five years, there were lots of sightings and rumours. At the second sighting in 2005, there were a lot of rabbits living in that particular area, and studies have shown that, when cats go wild, rabbits are a major source of their food.’’ Mr Guest, 58, who has worked for the Forestry Commission for 18 years, said these were the only two wild big cats he had seen in his career.

A survey by the British Big Cats Society showed more than 2,000 suspected big cat sightings were reported nationwide between 2004 and 2005.

The North-East and North Yorkshire are favourites for big cat reports.

Besides Gloucestershire, only Devon and Yorkshire recorded more sightings among the English regions during that time. There have also been several credible big cat sightings in County Durham and Northumberland.

Most wild cat sightings are attributed to panthers, with a handful of reports put down to their smaller cousins the lynx, once native in this country.

Their freedom in the wild is attributed to a range of sources from escaped zoo and circus animals to a mass release in the 1970s after the enforcement of the Dangerous Wild Animals Act.