The bombers are thought to be the Justice Department, the most violent and extreme group yet to emerge from the animal rights movement. Fawcett has been on the receiving end of several Justice Department packages. One contained a razor-tipped mouse trap. Another, a hoax bomb this time, came wrapped in Christmas paper and was left near his stable block. Twice he has had to call out the police and the bomb disposal squad to blow up devices left at the gates of his house, which is now heavily protected.
The devices sent to Mr Fawcett are part of a wider, largely unreported campaign. Most of the bombs have been too small to merit much national publicity. The Justice Department cultivates a low profile which fits in with the police's desire to reduce the risk that they might be copied. The media have unwittingly complied.
But despite the lack of national publicity a clear pattern has built up of a sustained campaign mounted by a ruthless organisation. There were at least 31 bomb attacks against hunts and their followers during 1994 and scores of others against scientists involved in research and product testing on animals. Most of the devices are believed to have come from the Justice Department.
Prince Charles has been the target of several devices, including a rat- trap equipped with razor blades sent to him soon after he took his sons on their first fox hunt in October last year. Tom King, the former defence secretary, was sent an incendiary after defending fox-hunting in a debate on the Wild Mammals (Protection) Bill in March. Michael Howard, Home Secretary and architect of the Criminal Justice Act, received an incendiary at the same time. Neither device exploded.
But most of the targets have been more mundane: hunt kennels for instance. It's not just the scale of the campaign that worries the security forces who have been tracking the Justice Department's activities, it is also its sophistication. The Justice Department is employing bombing technology last used by the IRA in its early terrorist campaigns. They frequently plant sophisticated hoax bombs, designed to frighten rather than kill. Several of the Department's attacks last year involved sending or planting sophisticated hoax bombs which would have worked had the explosive not been replaced by dog food - to mimic an explosive when they were X-rayed.
More rarely the Department plants or sends through the post fully functioning devices capable of maiming and killing. Incendiary devices are a speciality. Other devices have involved razor-blade tipped mouse-traps, allegedly smeared with HIV-infected blood. These simple devices placed in an envelope can easily slice off a finger.
It is almost impossible to gather any definitive information on the Department. Its members will not talk directly to the press and the police refuse to reveal much information about them. Yet it is possible to build up a picture of their activities through odd bits of information available on the Internet, conversations with animal rights activists who are close to the Department and occasional bits of information available from police briefings.
The security forces have become increasingly concerned about the Department, although it is not yet ranked as a fully fledged terrorist threat. Deputy Assistant Commissioner John Howley, overall head of both the Special Branch and the anti-terrorist branch, said: "Animal rights extremist activity is not terrorism. There is a definition of terrorism contained in the Prevention of Terrorism Act and it is the advancement of political objectives by means of violence with a view to overthrowing the government. What these sorts of people are indulging in, while it is akin to what we would call terrorism or political violence, is not quite on the same level yet."
Sources inside the animal liberation movement say that there are probably less than 30 Department activists operating in separate cells of less than five people. They live apparently normal lives. Many will have jobs. They are unlikely to conform to the stereotype of the modern urban activist, a squatter in second-hand clothes and army fatigues. Often the only things they have in common are a love of animals and nocturnal activities involving explosives.
The Justice Department is thought to be the terrorist wing of the Animal Liberation Front (ALF), in the same way that the IRA was linked to its political wing Sinn Fein. But the Justice Department is far more extreme than the ALF. A more accurate role model might be the extremely violent Irish National Liberation Army, which broke away from the IRA. Despite the hype, the ALF is generally non-violent. A leading ALF activist explained: "You cannot be in favour of animal rights and at the same time attack people because at the end of the day people are animals, too."
Since its formation in 1976, the ALF has attacked thousands of research labs, animal breeding establishments, fur shops, and hunt kennels. Its main aim is to liberate animals and secondly to increase the cost of using them. The Justice Department believes people are legitimate targets. An active member of the animal rights movement said that the "ALF takes every precaution not to endanger life but the Justice Department argues that if animals were capable of fighting back there would be a lot of dead animal abusers around already".
Many in the mainstream animal rights movement see the Department's analogy between animal rights and the struggles to abolish slavery and emancipate women as "stupid and naive". Jim Barrington, director of the League Against Cruel Sports, says: "Their methods are counter-productive. There's no glory in a long parliamentary campaign or in shaking a tin on a street corner. They're looking for something else. They don't have the cause at heart."
The Justice Department disagrees. Shortly after the start of their campaign in October 1993, a spokesperson issued a statement saying : "We won't be asking anyone to stop messing with animals and will make no excuses for our violent intervention - they've had it too good for too long."
Its belief in its case for violence will only have been strengthened by the defeat of the anti-hunting clauses in the Wild Mammals (Protection) Bill in July. The Bill passed through the House of Commons by 253 votes to zero but the crucial clauses, which would have banned hunting, were talked out at the committee stage.
So the hunting season, which gets under way this week, promises to be one of the most violent yet. The Justice Department's targets are starting to fight back.
Hunters have played the heavy, sometimes beating up hunt saboteurs since the 1970s. Meanwhile the Chiddingfold, where Mr Fawcett rides, has even resorted to hiring security guards. But this year violence against hunt saboteurs increased. In March, two pickaxe-wielding followers of the Cheshire Foxhounds, Anthony Kirkham and Geoffrey Park, were found guilty of assaulting a group of anti-bloodsports campaigners. More sinister was the fire-bombing of Clive Richardson's house in Corby nine days ago. Mr Richardson, a prominent hunt saboteur, has become used to attacks by hunt followers and has often had buckets of intestines poured over his doorstep. In this latest attack a neighbour's car was bounced into the road to prevent fire engines reaching his burning garage. It was the second arson attack within a fortnight.
Mr Fawcett, meanwhile, says hunting needs a robust, but legal, defence: "We used to have this wonderful system where we deported these types of people or put them in the Army. Hunting is a nice clean healthy sport. Country people have got to stand up and be counted."