Harold Shipman killed at least 166 of his patients, a public inquiry is reportedly expected to rule.

The real number could be closer to 209, reports the Sunday Times.

That number would make him Britain's worst mass murderer.

Shipman, a family doctor from northern England, was convicted in January 2000 of killing 15 of his patients with lethal heroin injections.

He was widely believed to have killed many more.

Unlawful killing

Later this week Dame Janet Smith, the judge heading a public inquiry, will give individual verdicts in the cases of 429 of Shipman's patients.

They were mainly middle-aged and old but healthy women, who died in suspicious circumstances between 1974 and 1998, the paper reveals.

Dame Janet will rule unlawful killing in 166 of the cases regarded as "highly suspicious", the paper said.

She is also likely to rule that a further 43 patients died in "suspicious" circumstances.

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Her findings are based on police and medical records as well as relatives' testimony.

Dame Janet's interim report on the killings will be made public on Friday, the paper reports.

The number of Shipman's victims dwarfs previous British mass murderers such as Thomas Hamilton, who gunned down 16 children and their teacher at a school in Dunblane, Scotland, in 1996, and "House of Horrors" killer Fred West, who killed 12 young women in Gloucester.

Shipman, now 56, worked alone and had a drug addiction.

Recommendations

He was sentenced to life imprisonment for each of the 15 murders, and has been told by Home Secretary David Blunkett he will have to spend the rest of his days behind bars.

A government report released a year after Shipman's conviction said it was "horrific and inexplicable" that the scale of Shipman's killings went undetected for so long.

Dame Janet's inquiry is expected to make recommendations about the systems governing death and cremation certificates and the supply of controlled drugs to doctors.

Few of Shipman's victims had post-mortem examinations, many were cremated and he put false causes of death on death certificates.