A man has been mistakenly given a vasectomy by medics who were supposed to be performing a minor procedure on him, a hospital has admitted.

The patient, who has not been named, went to the Royal Liverpool hospital for a minor urological operation but was wrongly made sterile by a surgeon.

Medics tried to reverse the error but it is not known whether the operation was successful.

Health bosses at the Royal Liverpool and Broadgreen University Hospitals NHS Trust said they have apologised unreservedly to the patient. They said an internal investigation into the incident had been launched and the surgeon responsible had been suspended from carrying out operations pending the outcome.

An operation conducted on the wrong body part is classed as a "never event" by health officials. The incidents are regarded by the government as so serious they should never happen. Between April and September last year there were 148 such incidents recorded by NHS England.

A vasectomy is a minor operation, where the tubes that carry sperm from a man's testicles to the penis are cut, blocked or sealed. It is possible for a vasectomy to be reversed but the success rate is about 55%.

NHS guidance states: "Even if a surgeon manages to join up the vas deferens tubes again, pregnancy may still not be possible. This is why you should be certain before going ahead with the vasectomy."

The medical director of the Trust, Dr Peter Williams, said: "We can confirm that a patient who was scheduled to have different minor urological procedure was wrongly given a vasectomy. We greatly regret the distress that this has caused him. We have apologised unreservedly to the patient and we are offering him our full support.

"It is our duty, in the best interests of the patient, to uphold their confidentiality, therefore we cannot provide any further detail without their agreement.

"This is a serious incident and we are investigating this fully to understand why it occurred and how we can ensure it does not happen again. We take any incident such as this extremely seriously and report them at the highest level in the Trust and to our regulators.

"Since this incident, the surgeon has not been carrying out any operations, pending the findings of the investigation. In addition we are carrying out routine checks on compliance with the WHO [World Health Organisation] checklist and our surgical teams are compliant."