Six 'never event' mistakes have happened at Northampton General Hospital in the last three years, all of them in operating theatres.
NGH board papers show that between 2015 and 2018 six of the serious and avoidable blunders were recorded, including the latest one, where the local anaesthetic block was administered at the beginning of an operation to the wrong body part.
Commenting on the overall trend, Matthew Metcalfe, NGH's medical director, says: "This is associated with a recent cluster of other theatre related incidents in which some of the principles of safer surgery have not been fully adhered to".
Mr Metcalfe adds that he "has indicated that the policies and principles which underpin safer surgery are a matter of professional accountability and will be initiating a programme of work aimed at embedding this firmly at NGH."
A spokeswoman for Northamptonshire General Hospital said: "A never event is the name given to a preventable incident that should never happen if all safety protocols are followed.
"Although rare, a never event is completely unacceptable. We have a very strong culture of safety, and we were very pleased that was recognised in our recent inspection by the Care Quality Commission.
"Our patients deserve the highest standards of safety when they need our care, and that's why it's important that we're open and honest when things go wrong, no matter how rare that is."
During the same time frame, 39 serious incidents were also documented.
Four of the incidents, which happened between November and December, included one person dying after omissions in care following chemotherapy, a fall resulting in fractured neck of femur, a delay in diagnosing lung cancer and baby tertiary referral for cooling.