John Swinney: Demanded answers on GM

About five acres of the crop were damaged on that occasion and police enquiries are still continuing.

A police spokesman said three of those arrested were men, aged 21, 31 and 40 and the remaining two were women, aged 46 and 47.

He said all five were still in police custody and were due to appear at Dingwall Sheriff Court on Monday.

The area of damage at the crop trial site was "being assessed".

The issue of the safety of GM crops has continued to provoke fierce debate in Scotland.

Scottish National Party Leader John Swinney accused ministers of treating Scotland as a "live laboratory" during First Minister's Questions this week by permitting the field trials.

He cast doubt over Scottish Executive arguments that ministers have no legal grounds for banning the trials.

However, Deputy First Minister Jim Wallace insisted scientific advisers said there was no risk. Political commentators viewed the exchange as awkward for Mr Wallace, the Scottish Liberal Democrat leader.

'Legal grounds'

His party called for a moratorium on GM crops at their annual conference last weekend.

Delegates voted for a halt on trials despite being told by Ross Finnie, the Liberal Democrat rural affairs minister, that he had no legal powers to do this.

Mr Wallace told Mr Swinney at Holyrood that both the Liberal Democrats and the executive wanted a moratorium on the commercialisation of GM crops.

He added: "But as Mr Swinney knows, field trials would be illegal for ministers to prohibit unless there were particular legal grounds for doing so."

Green MSP Robin Harper asked the deputy first minister to explain the executive's definition of risk in relation to the trials.

The list MSP for Lothians said local people in the Black Isle were worried because the GM crops had begun to flower and produce pollen.

Mr Wallace said officials had advised ministers that there was no threat to human health or the environment which forced the executive to permit the field trials.