A star of Gaelic football has been exposed as being a leading participant in an illegal international dog-fighting ring.

Gerard Cavlan, 30, a member of Tyrone's 2003 All-Ireland Championship-winning side, helped to organise competitions in which pit bull terriers often fought to the death, an undercover investigation has revealed.

During secret filming by a BBC Northern Ireland documentary team, Cavlan, from Dungannon, Co Tyrone, boasted about the animals' strength and skill in a fight and claimed to have up to 15 dogs. Cavlan reportedly said of a dog: "Sure he had him in the chest, and he shook him and he shook him for 25 minutes. If he hadn't got you killed in half an hour... he was in trouble, you know. A real hard-mouthed dog."

Earlier this year Cavlan claimed that he was not involved in the savage sport when he avoided a prison term for possessing a badly scarred, unmuzzled pit bull terrier.

Even though he was fined £650 after pleading guilty to possession of a dangerous dog, and banned for five years from keeping certain breeds, his lawyer denied that the Gaelic Athletic Association star had any links to illegal activities. Cavlan had simply collected the dog from kennels for a man from Dublin, Dungannon Magistrates' Court was told. On appeal, the ban was lifted, even though the conviction was upheld.

But the BBC Northern Ireland Spotlight investigation will say tonight that Cavlan is actually the joint owner of a dog fighting operation known as The Bulldog Sanctuary Kennels.

The investigation, which took 17 months and infiltrated a dog-fighting gang based in Tandragee calling itself The Farmer Boys, also uncovered a trail to Finland where breeders prepare animals from as young as 10 months to be exported to Northern Ireland.

One breeder tells the documentary: "I've imported a lot of dogs so I know how to fool, fool the customs... all you need is a computer and a printer."

The investigation uncovered 15 illegal dog-fighting gangs in Northern Ireland - five in Belfast and some with connections to international organisations.

The Ulster Society for the Prevention of Cruelty to Animals is understood to be preparing to act on the revelations once the Spotlight programme has been screened.

Cavlan's sporting future now looks as bleak as that of Michael Vick, the US Atlanta Falcons star quarterback, who has just pleaded guilty to dog-fighting charges. Last Friday Vick was suspended indefinitely without pay by the National Football League.

Vick admitted to funding the dog-fighting operation and the gambling associated with it and to being complicit in the killing of at least six dogs that had underperformed. “I was ashamed and totally disappointed in myself, to say the least,” Vick said, adding: “Dog fighting is a terrible thing. I reject it.”

Cavlan was in the Tyrone team that lost to Meath in the quarter-finals of this year's All-Ireland Championships.

Earlier this year a magistrate warned him that he must remember his position as a role model. Fining him, Eamon King said: "We want people to imitate you in all that's good - that is, your successful football career. Not in the type of activity that takes place in backyards in the dark of night involving one animal going face-to-face against another."

Cavlan was unavailable for comment this morning, but the Belfast daily newspaper The Irish News quoted him as saying that he had been “the victim of entrapment”. He said: “I felt victimised by the BBC and this has been a witch-hunt from day one. This has caused considerable upheaval in my personal and sporting life and has also resulted in the closure of my business.”

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