The prime minister could be over-estimating the dangers posed by international terrorism, Hans Blix has suggested.

Speaking on Sunday, the former United Nations chief weapons inspector warned against reacting to fears rather than sound intelligence.

His comments come just days after Tony Blair warned of the "mortal danger" of not understanding the threat posed by a new breed of religious fundamentalist terrorists.

"I think we still over-estimate the danger of terror," Blix told BBC1's Breakfast with Frost programme.

"There are other things that are of equal, if not greater, magnitude, like the environmental global risks.

"When Blair says intelligence is becoming ever more important, then I think we have to be careful."

Blix added: "My criticism is that there should have been a bit more patience.

"If the inspections had gone of for a couple more months, then I think Mr Blair and others would have realised that many pieces of intelligence which they relied upon were not valid."

Meanwhile, the Conservatives stepped up their attack on the government's handling of the decision to go to war with Iraq.

Speaking at the party's spring conference in Harrogate , shadow foreign secretary Michael Ancram the prime minister had lost the trust of the public.

"It is often said that the first casualty of war is truth," Ancram said.

"Here truth is the inexorable casualty of Blair."