The health secretary has announced an independent inquiry into how GP Harold Shipman murdered 15 patients.

Alan Milburn told Parliament the Shipman case "should not be allowed to erode the bond that exists between doctor and patient".

His announcement came as Greater Manchester Police revealed they were investigating a further 146 cases of patients possibly murdered by Shipman.

Praising the NHS, Mr Milburn said: "We have one of the finest family doctor services in the world. It is imperative we protect that reputation."

He said although a determined criminal could defeat the system, the UK "must be confident we have the best systems for regulation".

"l have no doubt they have to be strengthened and changed," he said, adding the inquiry would be "careful and considered", had the support of Home Secretary Jack Straw, and would be made public.

The inquiry will be chaired by Lord Laming of Tewin, the former chief inspector of social services, and will report to Mr Milburn in the autumn.

It will examine:

• How best to safeguard patients
• Safeguards for isolated medical practices
• Access to restricted drugs
• The role of the NHS tribunal
• Accountability of the General Medical Council

Mr Milburn added doctors would now be regularly appraised, and doctors who gave "cause for concern" would be closely monitored.

The GMC would also be given the power to suspend GPs, which it does not currently have, he said.

Mr Milburn also agreed to consider setting up a helpline for people worried their relatives or friends may have been victims of Shipman.

But Mr Milburn did not focus purely on the inquiry's aims and said other pressing measures would be acted on immediately. They include:

• Cutting Shipman's salary immediately, so he does not receive a further month's wages under NHS tribunal regulations
• Possibly removing pension entitlements from those who seriously damage public confidence
• Removing Shipman from GMC registration
• Doctors must disclose criminal convictions before appointment
• GPs must report deaths in their surgeries
• Auditing of Shipman's past practice, including pattern of deaths
• Urgent review on death certification

Mr Milburn concluded by saying: "We owe it to the relatives of Shipman's victims to prevent a repetition of what happened in Hyde."

The General Medical Council (GMC) has announced it is holding an urgent hearing in order to strike off the GP, who has been taken to Strangeways Prison.

Tory health spokesman Liam Fox welcomed the inquriy.

"As a former GP myself, I have nothing but horror and disgust at the actions of Harold Shipman. I find it personally incomprehensible that any doctor could behave in such a way," he said.

Labour MP Tom Pendry told Mr Milburn: "The statement you have announced to the House today will go a long way to give comfort to my constituents in Hyde and, in particular, those whose lives have been shattered by the actions of this evil man."

Nick Harvey, for the Liberal Democrats, expressed his "shock and horror" at Shipman's "dreadful crimes".

Meanwhile, Greater Manchester Police is facing questions about why it failed to arrest Shipman earlier.

Altered records

An inquiry was launched in March 1998 after it emerged Shipman was signing at least five times more death certificates than similar GPs in Hyde, Greater Manchester, where he practised.

But detectives, tipped off by the coroner, did not notice Shipman had altered some of his victims' medical records retrospectively and failed to check Shipman's criminal record or his GMC history.

Marie West, Irene Turner, Lizzie Adams, Jean Lilley, Ivy Lomas, Muriel Grimshaw, Marie Quinn, Kathleen Wagstaff, Bianka Pomfret, Norah Nuttall, Pamela Hillier, Maureen Ward, Winifred Mellor, and Kathleen Grundy were all patients of Dr Shipman who died between 1995 and 1998.

The 15 women were killed by lethal doses of diamorphine administered by the doctor, who also tried to gain �386,000 by forging the will of 81-year-old Mrs Grundy.