A controversial experiment to save racing pigeons across Scotland from being torn to pieces by sparrowhawks will go ahead despite objections from the government's conservation advisers.

From now until the end of March, hawks from around pigeon lofts near Glasgow, Edinburgh, Kilmarnock, Stirling and Dumfries will be forcibly relocated.

The trial is costing taxpayers £25,000 and is backed by the Scottish Homing Union, which represents Scotland's 3500 pigeon fanciers.

However, the government's conservation advisers have warned that it could be illegal and ineffective.

Disputes about the conflict between homing pigeons and sparrowhawks have raged for many years. The owners of urban doocots are angered when they see their birds being killed by the avian predators.

The relocation trial was originally due to start last March but was postponed at the last minute because of difficulties in getting licences from the UK government before the breeding season.

Since then, internal documents released under freedom of information legislation have revealed widespread doubts about the plan. The Scottish government's ecological adviser, Dr Ian Bainbridge, and Scottish Natural Heritage (SNH) have both privately expressed strong criticisms.

An expert legal opinion obtained by SNH has also been released to the Sunday Herald. It concludes that disturbing a bird of prey to protect pigeons regarded as private property "would be vulnerable to judicial challenge".

Nevertheless, the Scottish government asked for tenders to run the trial last November. Earlier this month, the environment minister, Michael Russell, told Labour MSP, Peter Peacock, that no bids had been received for the job.

So the government approached an "experienced raptor handler" who had previously expressed an interest in the work.

"The individual would prefer not to have their name released to the public at this stage," said a government spokeswoman.

Peacock blamed the difficulties in finding someone to run the trial on the widespread concerns about its suitability. "I am deeply sceptical about this whole experiment," he said.

"What is being tried is seeking to defeat the laws of nature and I don't believe that is possible. If someone complained to the European Union about this project, I suspect the government would be in serious trouble."

The trial has also been condemned by raptor experts, who argue that relocation will never be practical or acceptable. "It has set an unfortunate precedent," said Alan Heavisides, chairman of the Lothian and Borders Raptor Study Group.

The Green MSP Robin Harper has opposed the plan from the start. "It is misguided, misguiding and superfluous," he said.

"It will solve nothing, is against all the principles of biodiversity and conservation, cannot work, and will raise expectations which can never be met."