A British Muslim has been sentenced to 15 years in prison for being caught with a code book and instructions for firing a mortar.

Andrew Rowe, 43, was convicted Friday of possessing items likely to be used for terrorism.

An undated photograph released by London's Metropolitan Police of Andrew Rowe. (AP Photo/Metropolitian Police HO)

Prosecutors said traces of high explosives were detected on a pair of socks in Rowe's luggage after he was arrested at the French side of the Channel Tunnel in October 2003.

During the sentencing, the judge said Rowe was a paid operative who spread Muslim extremism.

Rowe testified he had used the socks as gloves for unloading ammunition in Bosnia in 1995 and had since used them to practice martial arts kicks.

A book containing notes on how to fire a mortar and a code substituting words such as "target" with cell phone models, were found at addresses connected to him in London and Birmingham.

Rowe said the notebook was a memento from Bosnia and the code would have been used to target courier drops for aid and arms to help Chechen separatists.

Prosecutor Mark Ellison said the code "made it possible to communicate in an innocent message which only spoke about mobile telephones."

Ellison said, "money" was "Nokia 3310," "trouble-police" was "3410," "weapon" was "3610," and "airport" was "3310."

A draft letter on the other side of the code book said Rowe was going abroad on "mobile phone business" and would be meeting someone who needed help.

Justice Adrian Fulford sentenced Rowe to consecutive sentences of seven-and-a-half years on each count.

Fulford said: "You were a paid operative over a substantial period of time, traveling the world and furthering the cause of Muslim fundamentalism."

Ken Macdonald, the director of public prosecutions, called the convictions a first success for his office's Counter-Terrorism Division, set up in May.

MacDonald said: "The challenge we successfully met was to prove to the jury that although there was no direct link between Andrew Rowe and a particular terrorist act, possession of those items together with other supporting evidence was sufficient for a jury to conclude that he had them for the purpose of terrorism."

Rowe, who was involved with drugs and petty crime as a teenager, said his conversion to Islam gave his life a direction.

He went to Croatia in 1995 as a volunteer driver to help Bosnian Muslims. Other travels took him to Indonesia, Malaysia, parts of Europe and Georgia bordering on Chechnya. Rowe also went to Morocco, Pakistan and Afghanistan.

A Malaysian newspaper reported last year that Rowe had met a French terrorist suspect, Lionel Dumont, at least twice in 2002 or 2003.

The report in the Star newspaper said the two were suspected of plotting an attack on London's Heathrow airport.

Britain staged a major security alert at Heathrow in February 2003, deploying tanks outside the terminal in reaction to what was described as a serious al-Qaeda threat.

Dumont, convicted in absentia of involvement with a criminal gang in northern France, is now in a French jail.