Death rates at 19 NHS hospital trusts in England were alarmingly high last year, according to an influential report.

Two of these trusts - Hull and East Yorkshire Hospitals NHS Trust and University Hospitals Birmingham NHS Foundation Trust - as well as two others also recorded a high number of deaths after surgery, the Dr Foster Hospital Guide found.

The measures are intended to act as a "smoke alarm" for where problems with care might exist.

Trusts also reported 56 incidents of "wrong site" surgery and 150 "foreign objects" left inside patients after an operation.

Researchers said many trusts were not accurately recording incidents of harm to patients, making it harder to prevent similar occurrences in the future.

Roger Taylor, director of research at Dr Foster said: ""Blood clots kill more people than superbugs every year - and yet the reporting of blood clots is just not always sufficient to identify and address the problem."