Prison officials feared that Shipman would take overdose

Prison authorities had concerns that Harold Shipman, Britain's most prolific serial killer, who hanged himself last week, may have been addicted to painkillers and been planning to take an overdose.

The revelation will prompt questions over why Shipman, suspected of killing more than 200 of his patients, was not regarded as a suicide risk and placed on a 15-minute watch while in jail.

Last Tuesday, the 58-year-old doctor was found dead in his cell at Wakefield prison in West Yorkshire, where he was serving a "whole-life" sentence. He had used bedsheets to hang himself.

Prison sources said last week there were suspicions as far back as last year that Shipman, who was then at Frankland prison in County Durham, may have been planning to commit suicide with prescription drugs secretly obtained while in jail.

Stephen Shaw, the Prisons Ombudsman, is heading the investigation into Shipman's death. It is understood he will be asking what medication the doctor was taking, what the pathologist found in his blood and whether there were any warning signs that Shipman intended to commit suicide.

The GP, who ran a practice in Hyde, Greater Manchester, was jailed in 2000 for murdering 15 of his patients with a lethal injection of diamorphine. An official inquiry later concluded that he had probably killed at least 215 people.

At the time of his conviction, it emerged that he had a history of addiction to prescription drugs, feeding his habit by making out forged prescriptions or overprescribing the drug to patients. He first became addicted to the painkiller pethidine more than 30 years ago, after a back injury. Eventually, he was admitted to hospital. In 1976, he pleaded guilty to 75 charges of forging prescriptions and stealing drugs to feed his addiction.

Shipman's death was greeted with anger by his victims, who say they will now never know how their relatives died or what motivated him to kill.

However, Mark Leech, founder of the ex-offenders' charity Unlock, writing in today's Independent on Sunday, says whole-life prisoners like Shipman - those who will never be allowed out - should be given the option of euthanasia. He says it would give such lifers - who include the Yorkshire Ripper, Peter Sutcliffe, and the Moors murderer Ian Brady - a "dignified way out".