A police marksman who had sex on duty with a woman while his loaded gun was in a holster around his ankles has been allowed to keep his job, it has emerged.

The police watchdog condemned Gwent police's handling of the case, saying it had omitted key details in a report.

PC Shaun Jenkins was originally dismissed from the force over the incident in 2010 but reinstated on appeal.

He used a police armed response vehicle to get a lift to the house where the woman was, and was inside for between 30 to 40 minutes during which time he said he continued to monitor the police radio.

Jenkins is now a neighbourhood beat officer, Gwent police said, having been removed from firearms duties after the incident was reported by the woman's husband.

The Independent Police Complaints Commission said on Monday that the way Gwent police had handled the matter brought the police discipline system into disrepute.

The incident happened in Caerphilly in April 2010. Jenkins was on patrol in an armed response vehicle when he told his colleague, also in the car, he needed to visit a house that he owned, and which he had rented out to the woman and her husband.

It was there the woman, who has not been named, and PC Jenkins had consensual sex, with his gun attached to his trousers, which were down around his ankles.

After the woman's husband found out and complained to police, the Gwent force sent a report to the IPCC that redacted key details, such as the fact PC Jenkins had his weapon on him.

The IPCC report said: "It was further established at this time that the investigating officer's report provided to the complainant and the IPCC had been redacted to remove the reference to a firearm. There was no evidence provided to the IPCC that the report had been redacted to remove this information."

The document recounting the incident, which Jenkins submitted, should have read: "On arrival at the address he describes that himself and (redacted) engaged in sexual activity. He states that he took off his body armour, leaving his T-shirt, and then took down his trousers to his ankles in order to engage in sexual activity.

"He confirmed that his sidearm was still attached to his trousers at the time, in its holster, and that it was loaded. Following intercourse he again asked PC Jones to give (redacted) a lift in the ARV to a location in the (redacted) area.

PC Jenkins confirmed that he was still monitoring his radio during his time in the property."

Jenkins was dismissed in January 2011 but a police appeal panel gave him his job back in April 2012.

IPCC commissioner for Wales Tom Davies criticised the panel: "The finding of the police appeals panel that the gun was never out of PC Jenkins' direct and immediate control because it was in a holster, attached to his trousers, which were attached to him, albeit around his ankles, is surprising.

"I am also bemused by the panel's conclusion that his conduct did not significantly downgrade the protection to the public because there was nothing to suggest he could not have been back in the police vehicle within a minute or two. These findings can only undermine public confidence in the credibility of the police discipline system.

"Any officer having sex on duty is unacceptable behaviour that falls well below what is expected of all police officers. Those who carry firearms are rightly subject to the highest standards of training, procedures and discipline.

"The manner in which this complaint was originally handled by Gwent police is unacceptable and their attempts to 'fast-track' the complaint and deal with it outside the formal regulations are not good enough."

The IPCC said that Supt Paul Griffiths, head of Gwent's professional standards department when the case was originally dealt with, had since been moved from that role.

In a statement Gwent police said: "Gwent police notes and fully accepts the findings of the IPCC report which was critical of the force's handling of a complaint against a serving officer.

"Our complaints handling processes have been reviewed and improved as part of our on-going efforts to ensure we provide the best possible service to the public."