Police said Bilal Abdullah is to appear in a London court on Saturday charged with conspiracy to cause explosions. Other suspects remain in custody pending a charging decision, the Crown Prosecution Service (CPS) said in a statement.

Prime Minister Gordon Brown said earlier on Friday that investigations stretching from Britain to Australia are "getting to the bottom" of a cell behind the failed car bombings in London and Scotland.

Brown said he had spoken to Australian Prime Minister John Howard about the probe into the suspected al Qaeda-linked plot, in which eight Middle Eastern and Indian medics have been arrested.

Australian police, already holding one Indian doctor since Monday, extended their probe to at least five others and searched two hospitals.

"This is an international investigation now," Brown said of the hunt for those behind two failed car bombs in London and a botched but fiery attack on Glasgow airport in Scotland by two men who smashed a jeep into a terminal building.

"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.

In a separate case, a court in Manchester sentenced a man described by police as a terrorist "sleeper" to nine years' jail for possessing a trove of al Qaeda-related computer material.

That followed the conviction of three other men this week for inciting terrorism over the Internet. Verdicts are due shortly in other trials -- part of a slew of cases that have highlighted Britain's appeal as a target for militant Islamists.

AL QAEDA LINKS

Brown has spoken of al Qaeda links to the latest plot, and British intelligence services are working with counterparts around the world to establish the extent of suspected involvement by Osama bin Laden's network or its Iraqi arm.

Bin Laden is seen as a potential threat on British home soil, not just in Iraq, where Britain joined the United States in the invasion to topple Saddam Hussein in 2003.

Although the London and Scottish attacks failed, they posed a test of nerve for Brown's new government in the first week after he replaced Tony Blair on June 27. For four days, security officials raised Britain's national threat warning to its highest level, before lowering it one notch on Wednesday.

The Australian link began with the arrest at Brisbane airport of Indian doctor Mohamed Haneef as he tried to leave the country on Monday. Police are examining more than 30,000 files on Haneef's laptop computer and a Sim card mobile phone device he left with one of the British bomb suspects. Haneef had previously worked as a doctor in England.

Medical authorities in Western Australia said two of those arrested in Britain, Sabeel Ahmed, 26, and Kafeel Ahmed, 27, had applied to work as doctors in the state but were rejected over concerns about their references.

Sabeel was arrested in Liverpool, northwest England, last Saturday evening. Hours earlier, Kafeel suffered critical burns in the attack on Glasgow airport in Scotland, where witnesses said he set both himself and the crashed jeep on fire.

Police and medical authorities said on Friday he had been moved to a hospital with a specialist burns unit. "He remains in critical condition," a Scottish health spokeswoman said.

A British security source confirmed the two Ahmeds were believed to be brothers from India. The official said investigators expected to spend many weeks piecing together all the suspects' backgrounds to determine how they met and where and when the plans for the attacks were formed.