Two hospitals have put up posters in operating theatres reminding surgeons to make sure they have got the right patients.

Oxford University Trust introduced the posters at John Radcliffe and Churchill hospitals after four patients received the wrong operation from May to June this year.

Known as ‘never events’, health bosses apologised for the errors which included the wrong patient receiving an endoscopy, a procedure where a thin tube fitted with a camera is run through the body via the throat.

Managers at the Trust, who also plan on introducing specialist staff training to tackle the issue, say the number of errors show no sign of decreasing.

Medical director Tony Berendt said: "No clinician in our hospital comes to work to be, in any sense, careless or to cause harm. I know that the teams that have been involved in these events are deeply upset about what has happened.

"On behalf of those clinicians I would extend my apologies to all patients involved and our public for the inevitable impact on their confidence in our services that these kind of events lead to. We do take them extremely seriously."