One of Scotland's most senior officers has called for traditional police roles such as conducting door-to-door inquiries and taking statements from witnesses to be handed over to civilians.

David Mulhern, chief executive of the newly formed Scottish Police Services Authority, also believes ministers should introduce police community support officers, whose growing use in England and Wales has sharply divided opinion.

His controversial comments on the need for radical reform and restructuring come on the day of a national debate in the Scottish Parliament on police resources. His views are expected to fuel the current row about the SNP's apparent U-turn on its manifesto pledge to introduce 1000 new officers.

Mr Mulhern believes the debate on whether Scotland needs an additional 1000 police officers is immaterial until forces can show that officers' time is not being wasted on work which could be done more cheaply by civilian staff.

His views, which are disclosed for the first time today in an exclusive interview with The Herald, are expected to set him at odds with the Police Federation and some of Scotland's eight chief constables.

Mr Mulhern also says a single body should handle all transport policing rather than relying on the eight forces with separate road traffic divisions and British Transport Police dealing with the railway network.

He would also be keen for the Scottish Crime and Drug Enforcement Agency to be given national responsibility for counter-terrorism and investigating fraud and complex homicides.

He claims officers should be trained as managers to oversee civilian officers who, in future, could take statements and conduct door-to-door interviews.

"Some 80% of the work done to investigate robbery, for example, is non-police specific but generally we get police officers to do it," he said.

"Doing door-to-door inquiries, organising the identity parade, phoning people and selecting other members of the public to be part of the parade and then running the parade could all be be done by someone other than a police officer.

"Yet, currently that is not the case. The one thing exclusive to a police officer is the power of arrest and if you don't need that power of arrest why would you necessarily want to see a police officer in that role.

"The first time you really need a police officer is to interview the person who has been selected in the parade. In England and Wales they are using retired detectives to do a range of those tasks involved in an investigation. You just need to give them civilians a list of five questions to ask in the door-to-door inquiries and get an administrator to arrange things."

Nicknamed "plastic plods", police community support officers were introduced to England and Wales in 2002. There are now 4000 with plans in place to recruit a further 21,000 by next year.

They get only three weeks' training, compared to 19 weeks for a police constable and do not have the power of arrest but can detain suspects for 30 minutes while they wait for regular officers to arrive.

The Police Federation in England and Wales has complained they are ineffective and cause more problems than they solve and the union is expected to oppose their introduction to Scotland.

Their starting salary of £19,000 is two-thirds that of a police constable.