The lowest death rate in the country was recorded by Royal Free Hampstead NHS Trust, while Barnet and Chase Farm Hospitals NHS Trust is still above the norm, according to figures published this week.

The Royal Free's mortality rate was 26 per cent below the national average from 2005/6, and 30 per cent below over the three-year period from 2003/6.

The mortality rate of Barnet and Chase Farm hospitals is six per cent above the national average for 2005/6, rising to 14 per cent when looked at over the three years from 2003/6. However, the Barnet and Chase Farm trust is still one of the ten most improved trusts in the country, with a 12.9 per cent decrease in mortality rate from last year.

The statistics were published on Tuesday by Dr Foster Research, an independent provider of NHS information. A hospital's mortality rate is calculated by assessing its performance against medical conditions that commonly account for deaths.

The chief executive of the Royal Free trust, Andrew Way, said: "I am absolutely delighted that the Royal Free continues to be the leading trust in the country for its mortality rate.

"This independent measure is a clear endorsement of the quality of our clinical services. It will reassure patients that we deliver excellent care and encourage them to make the Royal Free their hospital of choice."

Averil Dongworth, chief executive of the Barnet and Chase Farm trust, said: "Last year saw a number of important service improvements, for example cardiac catheterisation very specialised investigation of the heart, introduction of a paediatric assessment unit to avoid children waiting in A&E, and new services for older people.

"We now have shorter and more appropriate lengths of stay for our elderly patients, including shorter pre-operative length of stay in trauma and orthopaedics. We are also among the best hospitals in the country for the speed with which we see and treat patients with cancer."

mcraig@london.newsquest.co.uk