Image copyright PA

At least 309 police officers and police community support officers in the UK have been convicted of offences in the last three years, figures show.

The offences that led to convictions include sex crimes, assaults and possessing indecent images of children.

However, only 25 of the 45 forces gave figures to the Press Association after a Freedom of Information request.

A Home Office spokesman said measures had been introduced to improve standards of behaviour in the police.

The 20 forces that did not provide information either said they could not reveal the number of convictions because of the cost of retrieving the information, or did not respond to the request.

Police Scotland and the Police Service of Northern Ireland were among those not to provide the information.

Separate figures obtained from 18 forces showed that there are at least 295 officers and police community support officers (PCSOs) with convictions who are currently serving with the police.

Police convictions: How did your force respond?

'Appropriate action'

The Home Office spokesman said: "The vast majority of police officers in this country do their job honestly and with integrity. They put themselves in harm's way to protect the public.

"But the good work of the majority threatens to be damaged by a continuing series of events and revelations relating to police conduct.

"Over the last two years the Home Office has introduced a programme of measures to improve standards of behaviour in the police, including making the disciplinary system more independent and transparent through introducing hearings in public, preventing officers resigning or retiring to avoid dismissal, and - from next year - introducing legally qualified, independent chairs on misconduct hearing panels."

Police forces did not tell the Press Association the names of officers who had been involved in crimes, saying that it would breach data protection laws to identify them.

Analysis by BBC home affairs correspondent Danny Shaw

Image copyright PA

What the figures demonstrate is that, proportionately, the number of "rotten apples" in the police barrel is very small.

You might expect that, given that police are meant to enforce the law rather than break it, but sometimes newspaper headlines suggest the opposite.

However, the refusal of so many police forces to provide conviction data is more troubling. Surely it's in each constabulary's interest to keep tabs on employees with a criminal record - and surely it's in the public interest for us to know, for, as Home Secretary Theresa May has recently reminded us, the police are the public and the public are the police.

The College of Policing has begun releasing details of the number of officers who leave the service for disciplinary reasons. Perhaps the College, the body which sets ethical standards for the service, should start collecting and publishing conviction data too.

Among the forces to provide figures to the Press Association:

The Metropolitan Police, the UK's biggest force, said 178 police officers were convicted between 2012 and 31 March 2015 - while it refused the FoI request on costs grounds, it had already published this data. Of those, 54 were still serving, including 10 awaiting the conclusion of misconduct review hearings. Convictions in 2014, involving 46 officers, included two sexual offences, three thefts and 19 traffic offences.

Greater Manchester Police said 12 police officers and five PCSOs had been convicted since 2012. These include a male sergeant convicted of misconduct in public office, a male inspector convicted of fraud and a male PC convicted of possessing class B drugs, with other offences including perjury, theft and possession of offensive weapons. Five police officers and five PCSOs currently serving have previous convictions.

Devon and Cornwall Police said five police officers and five PCSOs had been convicted since 2012, with one officer convicted of possessing indecent images of children and two convicted of indecent exposure. A total of five had convictions committed before they were recruited.

Durham Constabulary said a male police constable was convicted of possessing indecent images of children in 2012 and that a male PCSO was convicted of common assault on a female member of the public while on duty in 2013.

There are 207,140 police workers in England and Wales according to the most recent government data - this figure includes police officers and PCSOs but also staff working in a support role. There are 17,295 full-time police officers at Police Scotland and 6,748 regular officers working for the Police Service of Northern Ireland, neither of which have PCSOs.

Officer was 'under stress'

Image caption David Knopwood had been a police officer for 24 years

The highest-ranked officer to have been convicted in the three-year period was a detective chief superintendent at West Yorkshire Police.

David Knopwood was sacked from the force for gross misconduct last year after admitting driving at nearly twice the legal alcohol limit.

He was banned from driving for 12 months and fined £1,000 at his court hearing last year.

He had failed a roadside breath test after being stopped by officers and admitted refusing to provide a further specimen.

The court hearing was told he drank two pints and then provided a roadside reading of 60 microgrammes of alcohol per 100 millilitres of breath. The legal limit is 35.

His lawyer had said Knopwood was under a lot of stress and had great responsibility at the force as the head of the unit responsible for investigating major crimes.

Cleveland Chief Constable Jacqui Cheer, the lead on professional standards and ethics at the National Police Chiefs' Council, said its code of ethics was "well-embedded across the service" - 12 months after being introduced - and that it "clearly sets out the standards of professional behaviour expected of officers and staff".

She said: "When members of the service fall short of these standards, well-established and rigorous processes are in place to ensure appropriate action is taken.

"The decision by a force to retain someone with a conviction will have been carefully considered and only taken following a clear, national and regulated process."

Victim Support director Lucy Hastings said: "As a charity that supports hundreds of thousands of crime victims every year we know that the vast majority of police are honest, trustworthy and committed to getting justice for victims.

"Victims of crime will clearly find these figures alarming. It is critical that victims know they can trust the police so that they have confidence to report crimes. But, understandably, it can be incredibly difficult to speak out about a crime committed by a police officer - someone we expect and trust to abide by the law."