SERIOUS doubts have been cast over planned new controls of air guns after Scotland's most senior frontline officers warned licensing would be too expensive and unwieldy.

The move is likely to cause embarrassment, coming days after the Scottish Government announced new laws to license air weapons as part of its last programme of legislation before the 2014 independence referendum.

The licensing of air weapons was a key part of the SNP's manifesto and for years focused tension between Westminster and Holyrood because it was an area reserved to the UK Government.

The Calman Commission recommended that powers on air weapons be devolved to Scotland and this was taken forward through the Scotland Act 2012 at Westminster.

However, the Association of Scottish Police Superintendents (ASPS) has now asked the Scottish Government to reconsider the plan to license all air guns north of the border, partly because there are so many in Scotland that the additional cost and burden on police would be considerable at a time of shrinking budgets. They also point out most owners are law abiding.

While Scotland's 50,000 firearms are already licensed under UK-wide legislation, the 500,000 air weapons in circulation are not.

The campaign to tighten air gun controls gathered momentum after the death of two-year-old Andrew Morton in Glasgow in 2005, who was shot in the head with an airgun pellet by a drug addict.

A paper from ASPS states: "The scale of the challenge around licensing and ongoing enforcement of any new legislation must not be underestimated. The costs of undertaking this must be made as clear as possible.

"There will be costs to businesses involved in supplying air weapons and associated products, to the public owning air weapons in complying with any legislation around licensing, costs to policing for operating the licensing process and enforcing the legislation and costs to the courts systems for dealing with any breaches of the legislation.

"While ASPS support the principle behind the drive for legislation - criminal use of air weapons is unacceptable and improved control may assist with prevention and lead to fewer victims of crime - it is the practical issues that give cause for concern. The challenges around getting any licensing of air weapons right are varied and complex.

"In the face of reducing policing budgets will it be possible for policing to absorb the costs of operating an air weapons licensing process and enforcing new laws?"

The number of offences in Scotland involving firearms has more than halved in the past five years, with roughly a third of offences relating to air weapons.

Chief Superintendent David O'Connor, president of ASPS, said: "Air weapons are very popular in Scotland. Most are used responsibly by law abiding people. Any legislation brought forward will be challenging from a cost and enforcement point of view.

"It is important that any air weapon licensing legislation is subject to robust scrutiny at the Scottish Parliament on grounds of proportionality, affordability and feasibility in terms of practical implementation."

A Scottish Government spokeswoman said: "We have engaged with, and continue to listen to, those who work within the industry to ensure this is a licensing regime that is practicable and affordable.

"We are working closely with Police Scotland, who are helping us deliver our commitment to introduce a system that enables them to better protect our communities by taking these potentially lethal weapons out of the hands of those who would misuse them.

"It is simply not right that in a modern Scotland airguns are available without a licence. That is why we will be introducing legislation in the coming session."