For nine months police and intelligence agents in eight countries have patiently worked through a forest of e-mails and intercepted telephone calls that have so far led to the arrest of up to 30 men.

Most of these suspects have never met. They had no need. They were recruited, groomed by skilled propagandists and schooled in bombmaking via the internet.

A senior security source told The Times that there is a far greater number of terror networks operating in Britain than had been thought, all using the internet to plot attacks here and abroad.

A series of criminal trials in Britain, the US, Canada and Bosnia over the coming months will determine whether the much maligned Western security agencies have successfully disrupted a dangerous ring of al-Qaeda sympathisers or been duped by faulty intelligence.

In a week when the competence of Scotland Yard and MI5 is being questioned, the outcome of what police here codenamed Operation Mazhar will demonstrate whether the long-promised co-operation of rival international intelligence agencies is succeeding. The operation is not connected to the raid in Forest Gate, London.

The arrest of 17 suspects, many of them teenagers, picked up in the suburbs of Toronto at the weekend is said to be the latest stage in dismantling a terrorist nexus that, worryingly, has its links with one of the world’s most wanted men — Abu Musab al-Zarqawi, leader of al-Qaeda in Iraq.

On his website al-Zarqawi has encouraged young Muslims to take up the fight in their own countries and spread his religious war further than Iraq and Afghanistan.

One aim is to create an army of “white-skinned” militants, men born in Europe and America who can convert to Islam and become harder for the authorities to detect as they cross the world on their missions, including suicide attacks. Using skilled computer operators around the world, al-Zarqawi’s outfit passes on bombmaking manuals, advice on how to sustain terror cells and even ways to use credit card fraud to hack into vital internet sites.

These are home-grown recruits planning to follow the example of the 7/7 bombers in London and bring devastation to their own backyards. The Royal Canadian Mounted Police claims that the gang it intercepted was set to bomb the country’s financial centre and the Parliament in Ottawa using vans packed with explosives.

These rival cells had no need to visit one another and risk being shadowed. Instead, with a few key strokes, the groups reportedly kept in touch with each other’s progress and synchronised their attacks.

A series of raids in recent months in a number of Europe’s capitals and in Atlanta in the US has passed virtually unannounced.

One US official told the Wall Street Journal: “We let the operation run as long as we had to make sure we could identify as many would-be terrorist operators as we could and then picked them off one, two, three and finally 17 at a time.”

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