An animal welfare charity said it was shocked by the scale of organised badger persecution it has uncovered in Northern Ireland.
As part of a two-year operation, the USPCA has been tracking one Belfast-based gang for some time.
The gang - one of nearly 20 the charity has identified - went out up to three times a week, using dogs to target several setts each time.
It is illegal to harm a badger or to damage a sett.
The USPCA obtained undercover footage which shows the gang digging at two setts.
Speaking as the operation to disrupt the activity nears its climax, the USPCA's chief executive, Stephen Philpott, described the targeting of badger setts by gangs of men with dogs as the worst cruelty he had come across in more than two decades of working with animals.
"The first thing that amazed us was the number of people that were involved in this," he said.
"For years we thought a lot of it was bar room myth.
"We were stunned to find that there were large numbers of individuals who were actually involved and got together in groups and communicated with each other on internet forums.
Mr Philpott said the gangs "actively planned and carried out organised badger persecution".
He said: "You're talking about a huge number of setts being targeted right across Northern Ireland week in, week out".
Operatives working for the USPCA used a range of hi-tech equipment, including an aerial drone with a camera on board to film the gang attacking active badger setts - one of the first times such activity has been caught on camera anywhere in the UK or Ireland.
Ian Hutchinson, one of the UK's leading experts on badger crime, later confirmed that the setts were active.
"I think these people think they're involved in country pursuits, but they're not," he said.
"There's almost always some other form of criminality involved with these people. They're coming out into the countryside, they're terrifying the locals, intimidating them.'Absolutely disgusting'
"They're going onto people's land without permission and basically engaging in the cruellest of sports, if you could call it a sport."
As they watched the gang at one of the locations, the USPCA became convinced a terrier, which had been put into the sett, had encountered a badger underground.
End Quote Stephen Philpott USPCA chief executive
You cannot deploy methods that were used in the dark ages to deal with a perceived problem against your livestock”
As the men began to dig down into the sett, the USPCA launched their drone and flew it over them. The gang fled, leaving their terrier in the sett. It was later recovered by the USPCA.
The dog was wearing a radio transmitter on its collar which enabled the gang to track its movement underground so they could dig into the sett when it encountered a badger.
Mr Philpott said: "I would stress to you, the USPCA's job is not about catching people. We don't use this technology to catch people.
"That's the job of the PSNI and on most occasions they're very good at it.
"What this is to do is to protect animals; it's to protect badger setts and to protect badgers. And that day we couldn't hold back any longer.
"We firmly believed that there was a badger engaged underground that was going to be persecuted, brought above ground and killed and so I gave the order to put the 'copter up."
The charity believes that some farmers and landowners have been turning a blind eye to the gangs digging on their lands. Many farmers believe badgers spread TB to cattle, a claim still debated by scientists.
Mr Philpott questioned the reasoning behind farmers' calls for a cull and said nothing could justify illegal badger digging.
"You cannot deploy methods that were used in the dark ages to deal with a perceived problem against your livestock," he said.
"It's absolutely disgusting. The USPCA campaigns for a dignified life and a dignified death for all animals. The badger in Northern Ireland gets neither."
Gordon Adair's exclusive reports on the USPCA operation will be broadcast on BBC Newsline at 18:30 GMT all this week.