One of the men is under armed guard fighting for his life in hospital after suffering 90 per cent burns.
International inquiry

Gordon Brown, the British prime minister, said on Friday that investigations stretching from Britain to Australia are "getting to the bottom" of the failed attacks.

Australian police have interviewed at least five other doctors since Monday and searched two hospitals.

Brown said he had spoken to John Howard, the Australian prime minister, about the inquiry into the discovery of two cars packed with nails and gas canisters in central London and the jeep which was crashed at Glasgow airport.

"This is an international investigation now," Brown said.

"I believe that, from what I know, we're getting to the bottom of this cell that has been responsible for what is happening," he told the BBC.