The retired doctor, at the centre of the Gosport War Memorial Hospital scandal, could face murder charges over the deaths of hundreds of patients who were needlessly given powerful opiate painkillers, the police have said.

A total of 456 people had their lives cut short and another 200 were "probably" given drugs without medical justification between 1987 and 2001.

An official inquiry last year concluded that Dr Jane Barton, 71, who worked at the hospital between 1988 and 2000, had presided over an "institutionalised regime" which had a flagrant "disregard for human life".

A damning report revealed how patients who were viewed as a "nuisance" were given opiates via syringe drivers, often resulting in their deaths within days.

Three previous police investigations have failed to bring anyone to justice, but yesterday senior officers vowed to get to the bottom of the scandal and determine whether the prescribing of the opiates led directly to patient deaths.