Chief Constable Sir Stephen House said rising numbers of thefts and robberies, particularly in the east, and sexual offending were jeopardising the record.
A 39-year low in crime and 1,000 extra officers on the streets are among the government’s proudest achievements.
Maintaining that low was always likely to be difficult during a year of reorganisation, with eight regional forces merging to one, and budget cuts of around £60 million a year.
However, Sir Stephen has previously said that should not be an excuse.
He told a Scottish Police Authority meeting in Kilmarnock yesterday: “We are seeing an increase in sexual offences, a significant increase particularly in rape assaults.”
He added that crimes of dishonesty were up, by 2.8 per cent, as were vehicle crime and theft.
“We have seen a huge increase in acquisitive crime. The biggest increase has been in Edinburgh.”
He added: “We’re seeing high numbers in a very short period of time and we want to understand what is going on. There is a danger of pushing overall crime figures up.”
Sir Stephen admitted he was surprised by the figures.
“Acquisitive” crime has fallen in the past decade, partly because of improved home and car security.”
He said it was likely there had been an increase in sheds being broken into, and admitted police figures were not as clear as he would hope and that seasonal adjustment was necessary.
However, compared to last year, crimes of indecency were up 16.8 per cent. Crimes of violence were down 13.9 per cent, and vandalism and other reckless conduct by 10.5 per cent.
The rise in sexual crime could be because victims were more confident about coming forward, while more historical cases have been reported following the Jimmy Savile scandal.
There has also been a 2.5 per cent rise in “group five” crimes: those “driven by proactive policing”, including possession of drugs and weapons. He said this was down to positive use of stop and search.
The warning of a possible rise in crime alarmed politicians. Graeme Pearson MSP, Scottish Labour justice spokesman, said: “These remarks will be of concern to everyone. But, importantly, they also call into question SNP policies.
“If the SNP’s policy of cutting the police budget, cutting vital civilian staff, but ensuring a certain number of police officer numbers is the right policy – why is the Chief Constable raising concerns about crime levels?”
Scottish Tory chief whip John Lamont MSP added: “Rising crime figures would be an unwelcome prize for the single force to claim in its debut year.”
Scottish Liberal Democrat spokeswoman Alison McInnes said: “If the Chief Constable believes this may be an issue, he must set out what he is doing to address this.”
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