The family of one of three women whose lives could have been saved if police had investigated serial killer Harold Shipman properly last night labelled the force as ''appallingly incompetent".

Greater Manchester Police apologised to the families of Winifred Mellor, Joan Melia and Kathleen Grundy after the Shipman Inquiry ruled that their lives could have been saved by a ''properly directed investigation".

Chief Superintendent David Sykes and Detective Inspector David Smith, the officers at the head of the March 1998 inquiry, which failed to uncover any evidence of the GP's killing spree, were out of their depth and unfit for the case, said the inquiry.

Shipman was eventually jailed for life in 2000 for the murder of 15 women, but is believed to have killed at least 215 of his patients.

Winifred Mellor's son, Danny, said: ''Today's report has just confirmed what we all knew - it was an appallingly incompetent police investigation.''

An initial internal inquiry into the investigation was no more than an attempt to brush aside criticism.''There was no sense of urgency," he said. ''It is the final nail in the coffin of Greater Manchester Police as far as I'm concerned.

''I am really disappointed. To find a body like the police acting in such a tardy manner is very disappointing.

''The police have apologised but until it is followed up by actions, and the people responsible are brought to book, it means nothing. I want Det Insp Smith and his superiors to face the consequences of their incompetence.''

Greater Manchester Police confirmed that Detective Inspector Smith was to face a misconduct investigation.

Inquiry chairman Dame Janet Smith - who also called for radical reform of the coroners' courts system - said an opportunity to uncover his crimes was missed in 1994 when Renate Overton was admitted to hospital after Shipman injected her with diamorphine.

She was in a coma for 14 months but died in April 1995.

Dame Janet said the lives of Shipman's last three victims would probably have been saved had a ''properly directed'' police investigation been carried out in March 1998.

There was a ''systems failure'' and the ''wrong people'' were appointed to the case.

Mr Sykes, who has since retired, was not experienced enough to supervise the investigation and did not realise that Det Insp Smith was ''out of his depth''.

Det Insp Smith did not fully understand the issues, made no record of his inquiries, failed to check Shipman's past convictions and did not pursue the fact that post-mortem examinations could have been performed on two victims Shipman killed shortly before his investigation began.

Fellow Hyde GP Dr Linda Reynolds had warned police that Shipman might have been using drugs to kill his patients.

In her 165-page report, Dame Janet said: ''Det Insp Smith was wrong to continue with his investigation, pretending that he knew what he was doing when, as he admitted in evidence, he did not know 'where to go'.''

But Dame Janet added: ''I must and do feel sympathy for those few who have been found responsible for the failure of this investigation.

''They must live with that for the rest of their lives.''

Home Secretary David Blunkett said it was ''essential that lessons are learned from these dreadful events".