More than 200 patients died unnecessarily at Medway Maritime Hospital last year, according to a damning report into death rates which is due to be published in full on Tuesday.

A review of patient safety is set to reveal that up to 3,400 patients died needlessly last year at 21 hospitals across the country run by the 14 NHS trusts.

The investigation into the hospital in Windmill Road, Gillingham was announced in February, in the wake of the scandal at Stafford Hospital where 1,200 patients died unnecessarily.

It is being led by NHS medical director Sir Bruce Keogh.

According to an initial report from the Keogh Mortality Review, the number of “excess deaths” at Medway Hospital for General Medicine was 232, “significantly higher than expected”.

All other types of treatment measured had below average death rates or within the expected range.

There are two overall indicators used to measure needless deaths, with anything more than 100 higher than expected. One puts the overall figure for Medway last year at 109, while the other is 113.

An initial assessment of the hospital said: “These two measures are being used as a ‘smoke alarm’ for identifying potential quality problems which warrant further review.

“No judgement about the actual quality of care being provided to patients is being made at this stage, or should be reached by looking at these measures in isolation.”

As well as death rates, safety, patient experience, leadership and effectiveness of treatment are being investigated.

Health secretary Jeremy Hunt is due to speak about the report in Parliament on Tuesday, and could call for drastic action to turn around the hospitals involved.

Measures could include closing units and issuing notices to improve. If progress isn’t made entire boards of directors could be sacked, it has been claimed.

Medway Hospital was investigated because its mortality rate on the Hospital Standardised Mortality Ratio (HSMR) stood out for two years in a row.

A Medway NHS Foundation Trust spokesman said at the time the investigation was announced: "The trust has been doing everything it can to understand the causes of a higher than average HSMR and to implement immediate actions where required.

"The trust welcomes further advice and input from the NHS Commissioning Board through this review process and is committed to ensuring a continued focus on the provision of high quality, safe care for its patients – working in partnership with families, carers and GPs.

The other trusts under investigation are: North Cumbria University Hospitals NHS Trust, United Lincolnshire Hospitals NHS Trust, George Eliot Hospital NHS Trust, Buckinghamshire Healthcare NHS Trust, Northern Lincolnshire and Goole Hospitals NHS Foundation Trust, The Dudley Group NHS Foundation Trust, Sherwood Forest Hospitals NHS Foundation Trust and Burton Hospitals NHS Foundation Trust.