Patients who have emergency surgery on the weekend are 11% more likely to die in the 30 days after the operation, compared to people treated on weekdays, according to UK researchers.

The research examined staffing levels in 156 NHS hospitals and found patients who go to less well staffed hospitals are 7% more likely to die than in better-staffed hospitals.

Experts at St George’s, University of London, found that three main factors were associated with whether a person is likely to survive 30 days after emergency surgery: the day of the week the patient was admitted and the number of consultant doctors, and nurses working.