“They not only let down the public, but they let down the many honest police officers who are doing an excellent job in very difficult conditions.”

Five of the allegations were so serious that the officers involved tendered their resignation.

The research shows that six of the officers have been under scrutiny for two separate allegations, which brings the total number of accusations handled by the PSD to 289.

Around a third of the investigations were resolved by the PSD or the force division, with a number of others discontinued or found to be unsubstantiated. Some 120 of the inquiries are ongoing.

Female officers were the subject of at least 49 of the allegations, although details on gender were withheld in 30 cases.

Force spokeswoman Eleri Morris said: “To put this figure into context, the 283 officers were either subject of a public complaint or internal misconduct procedures.

“It needs to be explained that these 283 officers were not all the subject of formal discipline.

“It has to be acknowledged that the majority of complaints against officers or internal misconduct results in either the matter being unsubstantiated or being dealt with by means of local resolution and/or managerial advice.

“It is comparatively few cases that result in formal discipline.”

The figures come after Llanelli inspectors Dyfed Bolton and Bob Price were temporarily removed from their Llanelli patches amid an investigation into alleged misconduct in an off-duty incident at the end of last year.