THE body representing rank-and-file police officers has warned of "alarming" political interference over stop and search powers.

The Scottish Police Federation has attacked both politicians and the new national force's own leadership over moves to strip constables of their rights to frisk members of public.

Its general secretary, Calum Steele, has written to every MSP warning that the debate on so-called non-statutory or consensual searches - those carried out without any specific suspicion - had "unearthed frightening levels of political ignorance".

Under attack from opposition leaders on the issue, First Minister Nicola Sturgeon last week said she had spoken to Chief Constable Sir Stephen House and that "consensual" searches would end.

Mr Steele responded in his open letter: "The events of the past week have resulted in a frightening narrative that politicians believe that they have a role to play in determining how and when police officers exercise their right to stop and search someone.

He added: "It is also alarming to read and hear reports that politicians consider that they are in a position to reach an agreement with or direct the Chief Constable of the day as to how and when such powers will be used."

Mr Steele's anger, which reflects the views of many Federation members, is aimed just as much as Sir Stephen as at the politicians.

Many officers believe figures for consensual stop-and-search were driven up by a targets-culture - one denied by the force itself.

This, officers believe, in turn sparked concern over non-statutory searches among some politicians.

Mr Steele said: "Regrettably the police service has to carry much of the responsibility for the hostility toward the subject of stop and search.

"The numbers-driven target approach to this area of policing was ill-conceived and resulted in attention being directed towards meaningless numbers rather than the sensible objective of crime prevention and detection."

The number of stop-searches boomed in the first year of Police Scotland as tactics adopted by Sir Stephen in the old Strathclyde force were rolled out across the company. They have since subsided.

Mr Steele said lessons had to be learned over stop-search. He said: "The greatest lesson of all however must stem from the historic warnings that a single police service in Scotland could become subject to political interference. "How quickly these concerns appear to have faded from the memories of those who now seek to exert what they so prophetically warned against.

He stressed that consensual searches were lawful - and supported by the courts. He said: "Are we really suggesting citizens should no longer be able to co-operate with police officers on a voluntary basis?"

Some officers contacted by The Herald fear that Scotland's tradition of non-confrontational stop-searches will now be replaced by more robust statutory ones such as those that have sparked riots in England.

Others believe that Sir Stephen's over-use of consensual stop-searches has already endangered public relations, especially with the young people most likely to be stopped.

Recent figures confirm the police continue to use non-statutory powers on some under-12s - despite the force admitting it did not think young children were able to consent.

Justice Secretary Michael Matheson has said he shares public "discomfort" over concessional searches of children - although he also stressed that youngsters do sometimes needed to be frisked, not least for their own safety.

A spokesman for Mr Matheson said that it was Sir Stephen who had suggested the force would consult on ending consensual searches.

He said: "We will explore whether any legislative changes are required once this process is concluded by the end of March.

"This robust and sensible approach will consider the issues fully to ensure the outcome properly balances the safety of communities in Scotland with proportionate and effective powers for police officers.

"It is crucial that this step is allowed to take place without political interference."

Assistant Chief Constable Nelson Telfer, speaking for the force, said: "The volume of stop and searches is monitored for accountability purposes, not a target for the force.

"We will now review the range of measures needed as we consider with our partners the replacing of all 'consensual' stop and searches going forward."