"I would have been appalled then, never mind now. The identification process was a farce, the court proceedings were a farce, the non-collection of available evidence was a farce.
"It's not acceptable by our own standards. The whole thing is a mockery of justice. I was appalled by it and I am appalled by it."
Shields is waiting to hear if he has been granted a re-trial by the authorities in Bulgaria.
His alleged victim, 26-year-old Martin Georgiev, was struck on the head with a paving slab during an early hours brawl outside a chip shop last May.
Shields was holidaying with friends after watching his beloved Liverpool FC win the Uefa Champions League in Istanbul.
The teenager has always insisted he had nothing to do with the fight and was asleep in his hotel room at the time.
Another Liverpool fan, 20-year-old Graham Sankey from Anfield, later issued a written "confession" to the attack, which the Bulgarian court refused to consider.
Mr Sankey's solicitor has since suggested it may have been an entirely different fight in which his client took part.
The findings of Mr Cole's investigation will be shown tonight on The Forgotten Fan: A Tonight Special at 9.45pm on ITV1.
