A police and crime commissioner is being investigated over an allegation of a historic sexual assault.

Steve Turner, the Cleveland Police and Crime Commissioner, is resisting pressure to resign following the revelation by the Mirror newspaper.

Mr Turner, a Conservative, was already in the spotlight after he was named in Parliament as having been cautioned some years ago for theft when he worked at a supermarket.

The police watchdog, the Independent Office for Police Conduct, has now begun an investigation into the allegation of a historic sexual offence, which will be carried out by another force.

An IOPC spokesperson said: “Any allegation that a criminal offence may have been committed by a police and crime commissioner (PCC) must be referred by the appropriate authority to the IOPC to determine whether the matter should be investigated.

“We have now begun a managed investigation following a complaint referral from the Cleveland Police and Crime Panel regarding the alleged conduct of the current PCC prior to taking up the role.

“This investigation, which follows an allegation of a serious non-recent criminal offence, will be carried out by a force from another area under our direction and control.

“We have contacted the complainant to make them aware of our involvement.

“As this investigation is at a very early stage, it would not be appropriate to comment further.”

Mr Turner’s office said he has no plans to resign or temporarily step down.

A spokesperson for the Office of the Police and Crime Commissioner said: “We have been made aware that a referral has been made to Cleveland Police and Crime Panel relating to a non-recent allegation against Police and Crime Commissioner Steve Turner.

“We extend our full co-operation to the panel and the IOPC and we will assist them with any inquiries they need to make.”

Mr Turner’s job is to oversee the workings of the police force and to give victims a voice.