The insurance industry has been plunged into the centre of a row between protesters and local authorities in the run-up to the meeting of the G8 nations.
Rally organisers G8 Alternatives are expecting hundreds of thousands of demonstrators to descend on Gleneagles on 6 July to protest against world poverty.
But Perth and Kinross Council has been unable to secure the £5m public liability cover it says is required.
Zurich Municipal, the council's insurer, has advised the authority that its existing policy does not cover it for an event of this size. The council said it then approached its broker, Marsh, to arrange alternative cover but was informed that no one was prepared to take it on.
A spokesman for Perth and Kinross Council said: "It is now down to G8 Alternatives, as the organisers, to secure the cover."
G8 Alternatives told Insurance Times that it would not stump up the estimated £30,000 premium but that the protest would still go ahead.
Andrew Smith, a member of G8 Alternatives, said: "The idea of insurance standing in the way of our democratic right to protest is ridiculous."