North Yorkshire Police chiefs are investigating why the force was the subject of 127 complaint cases between July and September this year, up from 82 in the same period in 2008.

More than 200 allegations in total were made against police officers, community support officers, special constables and support staff, usually for "failures of duty" and "incivility".

Police were also accused of assault, "oppressive conduct" and unlawful detention, and faced allegations relating to the improper disclosure of information and mishandling property.

Eighteen police officers were disciplined between July and September, including one who remains suspended.

Three officers received written warnings, including one who failed to properly investigate a traffic accident, while the other 14 received advice for "minor lapses in their conduct".

The force has begun disciplinary proceedings against 22 support staff since April, most commonly for using computers inappropriately.

Only 10 cases have been concluded, but already four employees have been sacked and five have received written warnings.

The figures come only two months after the force was landed with a £25,000 legal bill when a judge ruled its officers were wrong to arrest high-risk sex offender Robin Frampton.

Frampton was awarded more than £3,000 in compensation even though the judge at Leeds County Court agreed he had lied to police "left, right and centre" while in Selby to visit a vulnerable woman.

The force was also ordered to pay Frampton's costs as the court heard he had been kept in prison for four months before charges were dropped against him.

Police chiefs closed 21 malfeasance claim cases between July and September and paid claimants £4,162 in total.

But a report to North Yorkshire Police Authority warns that cases opened so far this year could potentially cost up to £180,000 in damages and in paying costs.

The force's head of complaints and professional standards, Superintendent Lewis Raw, said the "marked increase" in complaints was being examined.

"Every effort will be made to ensure a downward trend in complaints, especially those around 'incivility' and 'failures of duty'," he said.

"The force is also mindful that the rate of complaints per 1,000 officers is above the national average."

Complaints against North Yorkshire Police fell by three per cent in 2008-09 according to the Independent Police Complaints Commission. Humberside Police saw a 12 per cent rise in complaints, West Yorkshire 10 per cent and South Yorkshire a five per cent increase.