Hospital trusts in England that have been judged to be “significantly underperforming” on a range of measures of patient safety are considering taking legal action against the independent assessment body known as Dr Foster.

Its guide, How Safe is Your Hospital?, compiled by researchers at the Dr Foster Intelligence Unit at Imperial College London, ranked 12 NHS trusts in the lowest category for patient safety. The findings contrast with those published last month by the NHS quality watchdog, the Care Quality Commission, which showed that overall care at eight of the trusts was good or excellent.

The Dr Foster unit used 13 indicators to assess safety in hospitals, including hospital standardised mortality rates for all admissions and for specific conditions, such as stroke and acute myocardial infarction, together with adherence to …