Under Section 44 of the act, officers would be able to stop and search anyone they believe may pose a threat to security. Section 43 would give them the right to detain suspects without charge.

However, before the powers can be used, Home Secretary Charles Clarke would have to give his authorisation.

Asked today whether Mr Clarke’s permission had been sought, a police G8 spokeswoman said, “No application has been made as yet.

“This is still very much a planning operation and, if circumstances merit it, an application will be made. We are still considering it.

“The provisions of Section 44 have been used on a number of occasions around high-profile events in London and further afield.

“We are examining how they work and how they might apply to the G8 Summit in Scotland.

“If the circumstances merit an application to the Home Secretary then this will be considered.

“It should be stressed that the provisions of Section 44 are there to allow the police to take a proportionate approach when judged necessary to assist in the prevention of acts of terrorism.”

The Scottish Human Rights Centre has voiced its concerns over the Section 44 powers claiming their use would be “extremely controversial”.

Chairman John Scott said, “It would represent an easy way for the police to deal with some people they suspect of being troublemakers and keep them out of circulation for the duration of the G8.”

Meanwhile, Tayside Police confirmed that security around the summit will be boosted by an unmanned airship which will use remote cameras to monitor the cordon around the venue.

The spokeswoman made it clear today, though, that the airship will have no infra-red capabilities which would suggest it is unlikely to be of much use during the hours of darkness.

However, she would not be drawn on how officers would prevent intruders breaking through the perimeter at night.