Fourteen potentially deadly failures were reported inside Birmingham hospitals and health providers in just eight months.
The failures - which happened between April and the end of November last year, are known as “never events”, because they are considered so serious that they should never happen.
The trust with the most never events in Birmingham was University Hospitals Birmingham NHS Foundation Trust, which had eight - equal to one a month.
That makes it the fourth-worst healthcare provider in the country for never events over the period.
There were a further four failures at Birmingham Women's and Children's Hospital NHS Foundation Trust, and two at Birmingham Community Healthcare NHS Foundation Trust.
The data, published by NHS England, only gives an outline of the nature of each failure.
They are counted in specific categories of error.
Two of the incidents at University Hospitals Birmingham were recorded as “Retained foreign object post procedure”.
This means items - which could include swabs, needles, instruments and guidewires - were left inside the patient's body after surgery or other medical procedures.
A further two incidents involved a patient being connected to an air flowmeter when they actually needed oxygen.
The fifth incident at the trust involved the misplacement of a tube running from either the mouth or the nose to the stomach, which carries a risk of death or severe harm.
The sixth involved a patient being given an overdose of insulin in a mixup, the seventh involved surgery being performed on the wrong patient or the wrong part of the body, and the eighth involved a patient being given the wrong implant or prosthesis.
Two incidents at Birmingham Women's and Children's Hospital NHS Foundation Trust involved the misplacement of tubes from the nose or
mouth to the stomach, while a further incident involved items being left in the body post-procedure.
All the other incidents involved surgery being performed on the wrong part of the body or person.
Over the eight months Birmingham was the second worst local authority in England for never events, after Lambeth.
Across England there were 344 never events recorded, with the most common type of incident involving surgery being performed on the wrong person or on the wrong part of the body.
Of those, 33 incidents involved dentists pulling out the wrong teeth.
In December, England’s chief inspector of hospitals called for a change in culture within the NHS to reduce the number of patients who experience avoidable harm.
A report published by the Care Quality Commission (CQC) found that too many people were being harmed because of lack of training and the complexity of the current safety system.
Professor Ted Baker, CQC’s Chief Inspector of Hospitals, said: “NHS staff do a remarkable job to keep patients safe.
“But despite their best efforts, never events and other patient safety incidents continue to happen.
"In theory these events are entirely preventable: in practice too many patients suffer harm.
“We know there is a strong commitment to patient safety within our NHS and we must support staff to give safety the priority it deserves.
“But there is a wider challenge for us all to effect the cultural change that we need, to have the humility to accept that we all can make errors – so we must plan everything we do with this in mind.
“This change in approach is essential if we are to create a just culture where learning is shared, and where solutions are created proactively to manage risk.
“Only then will we be able to reduce the toll of never events and the much greater number of other safety incidents.”
Hospital or Clinic // Number of Never Events
University Hospitals Birmingham NHS Foundation Trust // 8
Birmingham Women's and Children's Hospital NHS Foundation Trust // 4
Birmingham Community Healthcare NHS Foundation Trust // 2