Highly respected trainer Brendan Ingle has died at the age of 77, the British Boxing Board of Control has confirmed.
The Irishman became one of the domestic fight scene's most influential figures during a decorated career in which he trained four world champions, including Naseem Hamed and Johnny Nelson.
His gym in Wincobank, Sheffield continued to thrive when his sons Dominic and John assumed control, but it is Brendan Ingle who is still credited with inspiring its success.
Ingle initially established the Ingle Gym to provide a place for young people to train, and was made an MBE in 1998 for his services and contributions to British boxing and for his work with young people in Sheffield.
Ingle's success and that of his fighters owed much to his unique methods. If not the highest profile, Nelson perhaps represents Ingle's biggest success in the way he was transformed into a world champion having lost his first three fights.
Nelson was among those to pay tribute to Dublin-born Ingle.
"A good, good man has left this earth today," Nelson said on social media. "A good friend. A good father figure. And the best trainer in the world."
Dave Coldwell, another of Britain's leading trainers, said: "The man that started me off on the road to where I am. He changed so many lives that were going nowhere and did so much for the sport of boxing in the UK. Thoughts with his family, friends and all the fighters he worked with."
British heavyweight Tony Bellew said: "Brendan Ingle has left a legacy that very few can ever compare to, so sad."
Frank Warren, who promoted Hamed while he was trained by Ingle, said: "Deepest condolences to (wife) Alma and the Ingle family after the passing of trainer and mentor Brendan.
"Boxing has lost a legend and I will look back fondly on the many great moments we shared together in the sport. RIP my friend."
Brendan Ingle was born in Dublin but it was in Sheffield, at the Ingle Gym in Wincobank, where he truly made his mark.
He died on Friday aged 77 having trained four world champions and become one of British boxing's most influential figures.
Prince Naseem Hamed was the highest-profile of those but it is Johnny Nelson, who became the cruiserweight world champion having lost his first three fights, who perhaps represents Ingle's biggest success.
The 51-year-old Nelson wrote on social media: "A good, good man has left this earth. A good friend. A good father figure. And the best trainer in the world."
Ingle moved from Ireland to South Yorkshire when he was 18 and as a professional middleweight had 33 fights, winning 19.
It was in Wincobank that a local vicar asked Ingle to contribute to some community work to help youths, and where his organisation of a weekly dance at St Thomas' church hall led to the opening of his highly-respected gym.
"All the nutcases were coming in," he said in 1999. "After the Sunday dance people would turn out on to the street and start fighting down Newman Road.
"So after 11pm we'd lock the doors, I'd fetch the gloves out, which thinking about it now was crazy. I would referee. Nobody ever got hurt."
Ingle's unique methods - he would get fighters to sing the colours of the rainbow while they practised their footwork to improve their co-ordination - also inspired Clinton Woods and Junior Witter to world titles, and since his sons Dominic and John took control of the gym, Kell Brook has also graduated through the Ingle academy.
He was made an MBE in 1998 for his services and contributions to British boxing and also for his work with young people in Sheffield at the gym which keeps his famous sign: "Boxing can seriously damage your health, but teaches self-discipline and gets you fit. Smoking, drinking and drugs just damage your health."
Ingle led Nelson to his world tile in 1999, four years after Hamed began his reign at featherweight. Hamed proved to be the finest fighter the Irishman ever worked with while establishing himself as one of Britain's greats, but they parted ways in 1998 and their once-close relationship never recovered.
When Hamed was inducted into the International Boxing Hall of Fame in 2015 he spoke of his desire to apologise to his one-time mentor, but Ingle was reportedly unwilling to entertain him.
Sons Dominic and John have since ensured the Ingle Gym continues to thrive, with WBO middleweight champion Billy Joe Saunders relocating from Hertfordshire to train there.
There are others he also influenced, including Dave Coldwell and reformed convict Richard Towers, who continue to pass on his lessons and methods as trainers in gyms elsewhere.
Ingle was one of 15 siblings. He is survived by his wife Alma and five children.