POLICE have apologised after several trials were delayed for months because vital CCTV evidence was not available.

The new national force blamed "short-term staffing issues" for problems getting productions to Perth Sheriff Court yesterday.

It is understood the problem was local but, speaking in court, Sheriff William Wood said the matter was causing "significant issues".

Fiscal depute Rebecca Kynaston asked for at least four trials to be put off at Perth Sheriff Court yesterday and explained the fault lay with Police Scotland.

In the first case, alleging four assaults, she said: "Police are having problems with copying CCTV for all cases and we are constantly chasing them.

"It is an ongoing problem the Crown is having at the moment, which is out of our control."

Superintendent Andrew Allan, of Police Scotland's Criminal Justice team, said: "We are aware of this matter and are working with the Crown Office and Procurators Fiscal Service to resolve it as soon as possible and are taking steps to prioritise cases in which this type of evidence may be needed as a matter of urgency.

"Unfortunately this week we have had a number of short-term staffing issues which have happened simultaneously which has affected our performance and we apologise for any problems this has caused."

Sheriff Wood said: "There are significant difficulties, whether that be with man-power shortages or technical issues."

The sheriff said he had been left with no option in the circumstances but to postpone all of the trials until near the end of 2014.