Plymouth's Derriford Hospital reports five serious mistakes
A hospital has reported five "never events" since November which all relate to surgery or treatment to the wrong part of the body, its trust has said.
The patients, who were treated at Plymouth's Derriford Hospital, have not been "seriously or permanently harmed", Plymouth Hospitals Trust said.
The Department of Health says never events are "unacceptable".
The trust added it took the incidents "extremely seriously" and was taking appropriate action.
Never events are defined by the CQC as serious, largely preventable incidents which should not happen.
The trust said three related to surgery and two to radiological treatments or interventions.
In a statement the trust said: "In each instance, the patient involved is aware of the incident, has been offered an apology and will be involved in the full investigation."
It added that as a result it had revised the theatre safety plan.
It said: "In healthcare, an organisation that encourages staff to report incidents and works to create a learning culture is actually working towards better patient safety.
"Our staff are devastated when anything goes wrong because they come to work to help people and want to provide the highest standard of care every time."
It added that all never events were investigated and recommendations published.
"We perform 80,000 operations each year, some of them extremely complex and high-risk. We want to reassure anyone out there waiting to come in to be treated that the risk to them of something untoward happening is very, very small indeed," the trust said.
The Department of Health said across the country in 2010/11 there were 166 never events reported to strategic health authorities and in 2011/12 there were 326.
The Care Quality Commission (CQC), said: "We are still awaiting further information on these latest incidents before we decide our response, which could well include a further review and inspection at some time in the near future."