A judge in Birmingham, central England, told Hassan Tabbakh that the home-made devices could have been developed into viable bombs capable of causing death and destruction.

The 38-year-old physics graduate, who lived in the city, was convicted of "preparing for acts of terrorism" after a two-week trial.

A jury heard he had tried to make bombs using easily available materials such as fertiliser and had made handwritten notes about their design.

Judge Frank Chapman told Tabbakh he was not being punished for having Islamist beliefs or for supporting Osama bin Laden's extremist network and similar organisations.

But he added: "If you had developed this concept into a working bomb, there would have been great potential for destruction, injury and death."

Tabbakh, who claimed to have been tortured in his homeland, was given indefinite leave to remain in Britain in 2005 after applying for asylum, the court was told.

Prosecutor Max Hill said police had found numerous items following Tabbakh's arrest on December 18 last year that showed he was preparing to wage "Al-Qaeda-style" jihad or holy war.

They included computer files with speeches by bin Laden and the former leader of Al-Qaeda in Iraq, Abu Musab al-Zarqawi, plus footage of attacks on coalition forces.

Tabbakh, who denied the charge, claimed he had been making fireworks with the materials, for use at religious festivals.

Detectives said after the case that it was not clear what targets, if any, Tabbakh had identified, nor whether he was going to pass the bombs to someone else.

"We can only speculate as to the damage that might have been caused in our communities," said Superintendent Kenny Bell, of West Midlands Police.

"We believe he was making a practical attempt to make a bomb and we arrested him at the right time to maintain public safety."