Robert Thompson was the chubby one, who appeared to be more aggressive. During the trial, he became known as "the boy who did not cry". To witnesses of James's abduction, Thompson was "the boy in the mustard coat". He was the fifth of seven brothers growing up in a violent home.
Jon Venables, one of three children, was slightly taller, anxious-looking and apparently in thrall to his friend. He spent much of his time with his mother in a semi-detached house on a bleak estate, visiting his father's flat at weekends.
The boys went to the same school, and Thompson's mother, Ann, had been called to a crisis meeting about her son's truancy 10 days before the killing. The boys, who each had August birthdays, became closer friends after being held back a year at school.
During questioning, Thompson remained stonily silent. His coolness unnerved police. Venables collapsed after his arrest and wept for days. They were convicted after a 17-day hearing and ordered to be detained at Her Majesty's Pleasure. Both boys were said to be suffering from post- traumatic stress disorder.
Six years later, now 17, they are being held in private suites in separate secure local authority units managed by the social services inspectorate. Neither has shown any sign of aberrant behaviour, no violence, no disruption. They have access to television sets, watch censored videos and go to classes. Both have reached almost normal reading ability and Thompson is said to have a reasonably high IQ.
The boys are allowed unlimited visits from their parents, and are watched constantly by experts skilled in understanding violent and unpredictable behaviour. Psychiatrists have prodded and probed for years, but have little more insight as to why the boys killed James.
Since the trial, the boys have not laid eyes on each other. Apart from seeing each other in court, their mothers have also never met. Earlier this year, Thompson received a visit from Sir David Ramsbotham, the Chief Inspector of Prisons, apparently after an invitation from the youth's psychiatrist.
The meeting made a deep impression on Sir David who admired the boy's artwork and sympathised with him over his uncertain future. In October, Sir David called for the two killers to released as soon as possible after their 18th birthdays "to give them some chance to make a life". The chief inspector told the New Statesman magazine: "I have met Thompson. I formed a considerable admiration for the way he is being looked after and the way he has responded. He got a lot of exams, and he is a very good artist. I saw his work, and he is someone of some talent."
His view provoked a public furore which led to a humbling apology to Jack Straw, the Home Secretary, for overstepping his remit. But further reports emerged of Thompson apparently showing remorse for his crime. No longer the fat, aggressive ringleader, Thompson was described as being "tall and well-groomed".
Venables, who is reported to have put on weight, has also apparently made significant progress at his detention unit and is visited regularly by his parents, Susan and Neil, who also attended every day of the trial.