Questions are being asked about the involvement of terrier men in trail hunting.
Traditionally, terrier men accompanied hunts and encouraged their dogs to find, fight and flush out foxes that had gone underground. Foxes were then killed, or continued to be chased in the name of sport, according to the League Against Cruel Sports (LACS).
The 2004 Hunting Act, however, would signal the end of such activity as hunts switched to following a trail rather than live animals. So why are they still operating alongside hunts 13 years after fox hunting was banned?
Chris Luffingham, LACS' director of policy, communications and campaigns, said: "The big question that now needs to be asked is why are they accompanying hunts which claim they are not targeting animals but following an animal scent-based trail?
"The answer can only be that the hunts are still targeting and killing animals."
Terrier men are contracted by the hunts to accompany them, he explained.
"Usually on quad bikes, they are ever present at hunts, sometimes masked, and notorious for their violence towards anyone brave enough to question their activities. Terrier men have been convicted of a series of offences for assaulting people monitoring their activity," Mr Luffingham added.
"They carry spades to dig down to the terrified fox which is either shot or mauled by the terriers they keep in boxes on their quad bikes or flushed out to the hounds and literally ripped to pieces."
Using reports from monitors, he estimated that nearly 80 per cent of trail hunts were seen to be using terrier men.
Lee Moon, spokesperson for the Hunt Saboteurs Association, said: "The fact that so-called trail hunts still employ terrier men and have them in attendance during a hunt is one of the most blatant signs of illegal hunting.
"There is no possible justification for their presence if legitimate trail hunting is taking place. Even if it is legal, in very specific circumstances, to dig out a fox using terriers it surely wouldn't arise during a trail hunt as only an artificial trail should be hunted.
"Trail hunting is a myth created by the pro-hunters to legitimise their illegal hunting. The Hunting Act needs to be strengthened and one of the first amendments should be the abolition of terrier work."
Darryl Cunnington, who heads up the League Against Cruel Sports' team of investigators, said he had monitored hunts more than 150 times and seen trails laid on fewer than half a dozen occasions. He has recently been observing hunts across England which are followed by terrier men and hunt supporters on quad bikes.
"The terrier men are hired heavies. They are ever present, but they should be of no use whatsoever if the hunt was simply laying a trail.
"The terrible cruelty they inflict on foxes would horrify the British public and no doubt bring many to tears. We need to bring an end to the barbaric acts being perpetrated by the hunts and terrier men."
LACS is campaigning for the Hunting Act to be strengthened with a ban on terrier men.
Mr Luffingham said: "All the evidence suggests that putting dogs underground to chase and fight foxes leads to some of the worst cruelty associated with hunting. The use of dogs underground should be prohibited as part of the new, strengthened and effective anti-hunting legislation which we are currently calling for."
The Cheshire Monitors record incidents of illegal hunting and hand the evidence to the police.
"We monitor between two and four hunts per week. Terrier men are always present and always masked up. They regularly use threatening and intimidating behaviour, both verbal and physical towards us to prevent us from following and filming the hunt," said a spokesperson.
"The terrier men come 'tooled up' for illegal hunting. We never wear masks and use non-violent observation to openly monitor the hunt's activities.
"We have never seen a hunt laying a trail and it's unknown for the hunts we monitor not to chase foxes during a day's hunting. How many 'accidents' can you justify!
"Every time we go out we find badger setts freshly filled in by terrier men either the night before or on the morning of a hunt to prevent the fox hiding in the holes."
While some anti-hunt campaigners complain of a lack of co-operation - even hostility - from the police, Cheshire Monitors have "developed a positive working relationship" with the local force.
"Cheshire Police, within the confines of the law, take, consider and pursue all the evidence we give to them either about illegal hunting or about the terrier men," the spokesperson added.
"Sadly, not only is the Hunting Act unfit for purpose, but also this style of policing is unusual. We would like to see the relationship and the style of policing we have with Cheshire Police rolled out throughout the country. Then, perhaps, illegal hunting could be stopped once and for all."The Countryside Alliance, which continues to oppose the 2004 Hunting Act, was asked to contribute to this article. Although it declined to comment, it sets out its position on hunting here.