London - Rio Ferdinand has said he finds it "impossible to forgive" John Terry in a racism row involving his brother Anton.
However, he said he would have been prepared to again play for England alongside former international centre-back partner Terry if given the chance.
The cause of the fall-out between the pair came when Chelsea captain Terry used racist language between Chelsea and QPR in November 2011.
Terry was banned for four matches by the Football Association as a result of the incident, having been cleared of any wrongdoing in an earlier court case.
Rio Ferdinand, in an extract from his new autobiography #2sides, serialised in The Sun on Sunday, criticised Terry for failing to admit to his error and for never apologising directly to him or his brother.
"For me, the biggest idiot will always be John Terry," he said.
"As England captain and my centre-back partner he could have saved everyone a lot of pain by admitting immediately that he had used the words in the heat of the moment, but was no racist.
"I think that's probably what happened and what the truth is. Anton and I would've accepted that - instead he never gave us the chance.
"I've never actually spoken to John about the case. I no longer talk to him, but even three years later I find it impossible to forgive or forget the pain he put my family through."
Ferdinand said the incident led to Anton receiving death threats and to their mother having her windows smashed, receiving bullets in the post and ending up in hospital with a stress-related condition.
"We weren't best mates, but we were football buddies," he added of his relationship with Terry prior to the racism incident.
"Yet he just sat there and watched as my brother went through all that because of his stupidity. That was the betrayal, He tried to run away from what he'd done."
The former Manchester United defender, now with QPR, officially retired from international football in May 2013, having not played for England since 2011.
But he insisted he would have played alongside Terry despite the off-field issue.
"Strange as it might sound, I would've been happy to play for England alongside him," the 35-year-old added. "I've played with people I didn't like for years.
"There were some at Manchester United I wouldn't go for a drink with, call or text. But I played with them.Ferdinand also spoke of the end of his childhood friendship with Ashley Cole after the former England left-back spoke for Terry in court.
"Ashley Cole had long been a friend of mine. We've known each other since we were kids," Ferdinand said. "But for me it ended the day he decided to go to court in support of John Terry.
"Anton rang me and my head nearly blew off. He was betraying Anton, who he'd also known for years."
However, Ferdinand said he had been wrong to tweet that Cole, whom he believes had pressure put upon him to back Terry, was a "choc ice" - black on the outside, white on the inside.
"I shouldn't have done it, but it's what I felt at the time," Ferdinand said.