This fox was reared for a Yorkshire hunt to one end ... to be killed for pleasure

THESE ARE the frightened eyes of a three-month-old fox cub staring through the bars of a tiny cage where it could barely stand up on the floor of sliding mud. The cub was to be raised, fed, watered, cared for even, before being released in front of a pack of baying hounds and torn to pieces.

The RSPCA has now started an investigation to find out who was responsible for trapping and keeping a pair of cubs in filthy conditions. Prosecutions for cruelty could follow. But for animal rights activists, the crucial factor is that the discovery was made on land owned by a hunt.

For years, groups such as the League Against Cruel Sports and the RSPCA have heard reports of foxes being caught and kept in captivity to be "spontaneously" hunted. The practice, if proved, would fatally undermine the field sports arguments that the main reason for fox hunting is pest control.

The hunts have denied they do this. Even the creation of artificial earths, used to encourage foxes to settle and breed in a hunting area, was, said Peter Atkinson of the British Fields Sports Society, "very much a legacy of the past".

Anti-hunt activists, including the League Against Cruel Sports, have countered with lists of hunts which they claim are using artificial earths to breed foxes to kill. Among those named were the Beaufort Hunt, a favourite of Prince Charles, and the Thurlow Hunt in East Anglia, headed by the food millionaire Edmund Vestey, a chairman of the Masters of the Fox Hounds Association.

But the activists admit that what had been lacking had been irrefutable photographic evidence. Then, last week, the League Against Cruel Sports received a call which promised to provide that elusive proof. The information came from animal rights sympathisers in North Yorkshire. They had stumbled across what appeared to be a baited trap on a piece of land called Muscoates Whin. And that land was owned by the Sinnington Hunt.

The League put into practice a plan it had drawn up for exactly this situation. A local representative contacted the people providing the information, while at the same time an undercover operator was dispatched from London. The aim was to get on film the evidence which would prove for the first time the practice of trapping foxes by hunts.

The 45-year-old undercover operator has been working for the League for 27 years, and has a record of exposing animal cruelty. He very much looks the part of a country man, with clothes, demeanour and apparent views which would blend in with hunt supporters in their pubs and clubs. And that is where he gathers information. He does not want his identity revealed. According to the league, half a dozen of his colleagues have been attacked by country sport followers.

The undercover man travelled up to North Yorkshire earlier this week. He mixed with the locals and was taken to the spot where the trap was concealed. The foxes were there, along with some liver used to feed them, and a sheep carcass left nearby.

The League's aim was to witness and film not just the foxes which had been caught, but also the people who had caught them. However, despite a prolonged watch, this did not happen. There was also a danger that the agent might get discovered. He said last night: " We decided the thing to do was to carry out our filming. We had enough evidence, and to wait longer could have been counter-productive. The video camera is the best weapon against this kind of thing, it brings home to people just what kind of cruelty underpins the so-called glamour of hunting, the stirrup cups and the fancy coats.

"I think a lot of those who take part in hunting will feel very uneasy if they can only see what takes place to provide them with their sport.

"The sight of the cubs was terrible. I have been doing this kind of work for 27 years now, but I was very, very shocked.

"They were a pitiful sight, kept in disgraceful conditions, and very, very frightened. I know that hunting people say when artificial earths are created they should be kept dry, otherwise the animals will suffer and become sick. No such attempt had been made here. The ground was muddy and wet, and the cage was absolutely tiny."

After getting the footage, the RSPCA was alerted and they in turn contacted the police. Yesterday morning an officer from Helmsley police station accompanied RSPCA inspectors when they called on the Sinnington Hunt. The masters of the hunt could not be found, but a kennel huntsman and a terrier man were taken to the trap at Muscoates Whin.

Drainage rods had to be used to get the foxes out. They were taken to a vet and found to be suffering from mange. After treatment they would be taken to an animal sanctuary, and released in an area where there is no hunting.

In Baily's Hunting Directory, the Sinnington Hunt is described as having "several vale coverts which seldom fail to hold a fox". The League's chief officer, Graham Sirl said: "They have long boasted about their ability to find foxes for their followers to kill, and now we think we know how they do it. We have long suspected that hunts do this."

Despite that view, it is yet to be proved that the hunt's organisers knew or were responsible for what happened. That is now the subject of the RSPCA inquiry.

Those responsible may face animal cruelty charges both under Wild Mammals Protection Act of of l996 and, because the cubs had been held captive, under the Protection of Animals Act of 1911, which relates to domesticated animals or those in captivity.

A hunt spokeswoman said she was not aware of the discovery of the trap and did not wish to say anything more.