Andrew Wakefield had a job at the prestigious Royal Free hospital in London and a promising career ahead of him in February 1998 when the Lancet published his research paper which hypothesised a link between bowel disease in children and autism. Six years on, he has neither.

Mr Wakefield, 46, believes the medical establishment has frozen him out, putting obstacles in the way of his research and refusing to countenance or investigate his theories. Many doctors and scientists, however, consider that Mr Wakefield has behaved unprofessionally by refusing to listen to the criticism of his peers.

The bad feeling has led to a situation where Mr Wakefield will speak freely only to his supporters. He and his wife Carmel, also a doctor, are understood to feel besieged and beleaguered.

The chief medical officer, Sir Liam Donaldson, yesterday remarked that when he tried to contact Mr Wakefield, he found himself referred to the public relations firm Bell Pottinger - an extraordinary situation within the medical world. Journalists who have offered anything other than a favourable view of Mr Wakefield's theories have the same experience. He is available only to those who endorse his views.

Mr Wakefield was born into the medical establishment of which he is now such a controversial part. He followed in the footsteps of his GP mother and neurologist father to read medicine, and then went to study in Canada, qualifying as a surgeon (he is usually referred to as Mr, not Dr Wakefield). He became a fellow of the Royal College of Surgeons in 1985.

He specialised in transplant surgery and then went into gastroenterology - the study of the gut. He moved to London and became a research fellow at the Royal Free and University College school of medicine, where he set up the inflammatory bowel diseases study.

He had developed his theory that measles virus was in some way linked to bowel disease and autism some years before the Lancet article. The controversial paper had 12 authors from various specialities, and it categorically stated that no link had been established. At the press conference, however, Mr Wakefield broke ranks to suggest that the three vaccines in the triple MMR jab should perhaps be given separately. Nothing on that issue was said in the paper.

The storm that blew up around the suggestion of a link between autism and MMR and the suggestion that single vaccines were preferable caused the Department of Health to request the Medical Research Council to set up a top-level inquiry to pursue Mr Wakefield's research.

The scientists concluded that there was no evidence to support the claims. Mr Wakefield's critics, who now include some of his original co-authors, say they were startled by his categoric refusal to accept the criticism. From that point on, Mr Wakefield became ever more isolated, even as parents of autistic children flocked to him in their hundreds in the hope that he could explain what had happened to their children. He became a heroic figure to them. He continued in the same line of research, but against opposition at the Royal Free. Eventually he left his £50,000 job - by mutual agreement - in December 2001.

Mr Wakefield and his wife went to the US, where it was announced that he was to be director of research at the International Child Development Resource Center in Florida, which is linked to the Good News Doctor Foundation, a Christian ministry and has a special interest in autism.

He does not appear to be in the US full-time, however, and was recently heavily involved in the UK, advising on the controversial channel Five television docu-drama about his work, called Hearing the Silence, which was condemned as irresponsible and reckless by some doctors.