More than 2,000 police officers had at least three complaints made against them by members of the public over the past year, according to figures released today.
A BBC survey of UK forces showed 2,073 officers were subject to three or more allegations them during 2009/10.
Most complaints were about rudeness, assault or failure of duty, according to the Freedom of Information request.
The Police Force of Northern Ireland had the highest number of officers with three or more complaints, at 376.
The Metropolitan Police was second with 273 officers, followed by Greater Manchester with 160, Kent with 130 and West Mercia with 117.
Altogether, the statistics from 43 out of 52 constabularies showed more than 5,000 complaints were made against officers over the past year.
According to the BBC, in Dyfed-Powys 40 allegations were made against one inspector and 38 against one constable during the year.
One officer in the West Midlands was also made to wear a headcam on duty because of the allegations, while another had their Taser training deferred.
Of the minority of forces which provided details about the complaint outcomes, more than half led to no further action.
Deputy Chief Constable John Feavyour, of the Association of Chief Police Officers, said officers have thousands of interactions with members of the public each day and the vast majority were "positive for both the police and the public".
"However, where a member of the public considers an officer's conduct to be unsatisfactory or improper, we would encourage them to inform their police force, so that action can be taken where appropriate," he said.
"In this way, the service which we deliver can be continuously improved."
But he urged caution before using the findings to compare performance across the police service, saying that the procedure for handling complaints varies across forces.
"The Independent Police Complaints Commission (IPCC) will publish their annual report into complaints against the police during the autumn, which will provide a national picture on this issue as well as enabling comparisons to be made across forces and between recent years," he said.