The number of police officers will fall by around 400 over the next three years, it has been announced.

Scottish Police Authority chairman Andrew Flanagan made the announcement at a press conference about a consultation on Police Scotland's new ten-year policing plan.

As part of the new strategy, the force will aim to cut police officers who mainly work in corporate and backroom roles.

Police Scotland aim to then divert resources to front-line operations and a more visible community presence.

Flanagan said: "We are anticipating a small reduction in police officer numbers through to 2020.

"It would be around 400 but that would come towards the end of the period, rather than early on.

"We expect police officer numbers to remain at their current level through the coming year and only gradually reduce thereafter."

He added:"I must stress - we will not reduce police officer numbers until we see these productivity gains coming through.

"So, actually, we are anticipating the amount of operational policing will actually increase through the period through to 2020."

Chief constable Phil Gormley said: "Policing in Scotland has gone through significant transition; it is proudly one of the oldest public services in the world.

"Now the service must transform to realise and release the full benefits of being a single organisation.

"Local policing will remain at the heart of what we do, supported by a wide range of specialist capabilities."

According to the latest statistics, there are currently 17,256 officers in Scotland.

The SNP promised at both the 2007 and 2011 elections to introduce and keep 1000 additional police officers, ensuring the number did not fall below 17,234.

A similar pledge was not contained in the the party's 2016 manifesto:

Instead the party's latest manifesto said: "The nature of crime is changing and the police need to reflect this.

"We will therefore ensure that the police also have more specialists, such as experts in cyber-crime and counter-fraud and that the service has the right mix and numbers of staff for the future."

Welcoming the draft policing strategy and consultation, justice secretary Michael Matheson said: "I welcome the work to develop the draft strategy for public consultation to ensure Police Scotland keeps pace with the changing nature of crime and of society.

"I am particularly pleased to see the service's commitment to increase its operational capacity in critical areas."

He added: "While our programme for government is clear about the need to consider the right mix of skills and not just overall numbers, the public will always be interested in the number of police officers on the beat.

"We will pay particular attention to these issues before approval of the final strategy.

"In all circumstances, I would expect to see the number of police officers remaining significantly above the number we inherited in 2007."

Scottish Liberal Democrat justice spokesman Liam McArthur said: "This strategy represents an opportunity for the SNP government to admit where they went wrong with centralisation and, after years of mismanagement, help get the police service back on even footing.

"We need fundamental reform of how our police service operates. But the chief constable will struggle to deliver this without clarity and support from the Scottish Government.

"That starts with SNP ministers being upfront about whether its 1000 extra officers requirement is officially being been ditched."