But the doctors' professional conduct committee decided that Clive Froggatt should not be struck off the medical register, and instead referred his case to the GMC health committee.
The committee will decide whether his fitness to practise has been seriously impaired by his self-confessed drug-taking and he will have to submit to a full medical examination.
The committee could suspend him for a year or impose practise restrictions for up to three years, but it does not have the power to strike him off.
Froggatt had claimed that he was secretly obtaining diamorphine through forged prescriptions from chemists to conceal the fact that he was treating the late MP for Cheltenham, Sir Charles Irving.
In fact, the barrister, Rosalind Foster, said, Froggatt, 47, of Cheltenham, Gloucestershire, was getting 66 to 166mg of the drug a day on a long-term basis to satisfy his own addiction.
Ms Foster said that Froggatt, who was at the centre of Lady Thatcher's "privatisation" of the National Health Service, appeared at Bristol Crown Court on 28 April this year where he pleaded guilty to eight specimen charges of obtaining drugs by deception and was sentenced to 12 months' imprisonment, suspended for two years.
At the peak of the doctor's deception, he was visiting up to four different chemists in one day. In October 1993, for example, he presented a total of 4,710 prescriptions for 151 patients, Ms Foster said. He had used the names of people long since dead and of close friends, without their knowledge, to obtain the drugs.
Ms Foster said that during interviews with police, Froggatt had lied extensively, although he eventually admitted his addiction, claiming, amongst other things, that he had taken to cocaine, followed by heroin, after his failure to be elected president of the Royal College of General Practitioners. His heavy involvement in the NHS reforms and consequent unpopularity among sections of the health service had also contributed.
His excuse that he was covering up for obtaining drugs for the late Sir Charles was largely exploded as a myth when the MP was interviewed by police and said he had never received diamorphine from the doctor.
Ms Foster told the committee that the doctor's massive heroin addiction must have posed a serious threat to his patients.
There were several other extremely serious aspects to the case, she said, not least of which were the huge amounts of drugs involved and the fact that the NHS had been deprived of funds.
Anthony Arlidge QC, representing Froggatt, who was admitted as a member of the Royal College of Surgeons in 1970, said that one of the reasons he had started taking cocaine and heroin was the abuse he received because of his major role in the NHS reforms.Reuse content