He was born in Bargoed, and his own professional record was squeezed into five welterweight fights in 1963, comprising four wins and one defeat.
Most famously, he guided Johnny Owen through his professional career, all the way to his final, fatal fight against Lupe Pintor.
Gardiner remembered the night in a moving 2010 BBC interview to mark the 30-year anniversary of Owen’s demise.
“There were a lot of Mexicans in the auditorium, they gave us problems, it was jam-packed there. But Johnny was very professional, took it in his stride and started very well.
“Up to the eighth round everything was going really well, the American promoters were getting worried.
“Johnny looked so frail, they hadn’t even thought he could fight.
“He was bleeding very badly from his lip from the fourth round, but we didn’t think there was any trouble. I couldn’t have stopped the fight because it was going so well.
“The 10th and 11th went very well, then the disaster struck in the 12th. I knew it was bad straight away, he just crumbled.
“The Mexican crowd showered us with drink and everything else, they took all our equipment from the corner… [but] they didn’t realise how bad it was.
“I carry Johnny in my heart all the time, I always think of that fight. Every year around the time of the anniversary I go up to his grave.”