Thomas Mullen, the Dublin heroin dealer known as "The Boxer", has been jailed for 18 years in London for masterminding a £750,000 heroin smuggling operation in Britain.
The jury at Snaresbrook Crown Court in London deliberated for just over four hours yesterday before deciding that Mullen (26) was guilty.
Passing sentence, Judge Timothy King said: "You have been convicted in my view upon compelling evidence, indeed, some might consider it overwhelming evidence. Those who traffic in class A controlled drugs are the purveyors of misery, degradation and, all too frequently, death."
He instanced co-defendant Catherine Brooks, a drug addict who turned Queen's evidence after being caught smuggling 1kg of 43 per cent pure heroin. "One only needs to see a person like Catherine Brooks to see just what devastation can be brought on the life of an individual who is addicted to a drug like heroin."
Brooks, who admitted taking part in the conspiracy, will be sentenced on February 10th along with Turhan Mustafa, who admitted providing the heroin.
The judge added: "Those who control drug-trafficking seem to make the most money but they also seem to fall the furthest distance."
Judge King told Mullen: "For my part, I view the exportation of heroin as every bit as serious as its importation from abroad for use on the streets here. Wherever heroin is consumed, it has that evil and degrading effect.
"Exportation is another dimension of an evil and pernicious trade. This offence is so serious that only a serious custodial sentence can be justified." He added: "The least sentence I can pass is 18 years' imprisonment."
Det Sgt Dave Osborn of the North East London drugs squad, was called to the witness box before Judge King passed sentence. He told the judge: "As you are aware, myself and other colleagues have made inquiries in Ireland. I know myself, from these inquiries, that there is no doubt whatsoever that Mullen is considered to be the foremost drug trafficker in Dublin in the supply of heroin."
Mullen's defence counsel, Mr Gordon Pringle, said: "He and I recognise that we can say nothing." But he added: "He is a young man, a family man. He has no previous convictions of a similar nature."
Mullen, who was handcuffed to a prison guard throughout the trial, will be sent to a top-security prison in Britain. His brother John sat in the public gallery and looked straight ahead as the guilty verdict was read out.