Whittington Hospital came top of a list ranking mortality rates, meaning it has the lowest ratio of actual deaths to the number predicted according to the demographic of patients.

The rankings are based on the summary-level hospital mortality indicator, introduced by the Department Of Health last year, which compares the actual number of deaths at a hospital with the expected number of deaths based on national averages.

The actual number relates to the total number of patients admitted to the hospital who die either in hospital or within 30 days of being discharged.

“We are pleased to maintain our outstanding track record of excellent patient safety,” said a spokeswoman for the Royal Free. “This is down to the dedication and hard work of our staff.”

The hospital is joined in the top five by Royal Free Hospital in Hampstead , University College London Hospital, in Euston,  All three are part of the NHS North Central London cluster.

Alison Pointu, the cluster’s director of quality and safety, said: “For three of our hospitals to achieve such a positive result in national rankings is outstanding.

“Patients receiving treatment for serious and potentially life-threatening conditions can feel reassured that they are in the best hands.”

Tim Straughan, the NHS Information Centre chief executive, said the mortality indicator should be treated as a “smoke alarm” to help NHS trusts monitor their mortality rates.

The figures and details on how they are calculated are published quarterly on the NHS Information Centre’s website, www.ic.nhs.uk