Tawhid wal Jihad, a group led by Abu Musab al-Zarqawi, achieved global notoriety using technology developed by JelSoft, a company based in Ascot, Berkshire.

The company sells a software package on the internet that enables customers to create a website onto which pictures, film and words can be remotely downloaded.

Experts were last week assessing the prospect, however unlikely, of tracing the identity of the terrorists’ accomplices through JelSoft’s licensing records.

The fact that JelSoft’s web services could be used by terrorists without its knowledge highlights the problem of anonymity that the internet affords. Technology invented by the West is now being used against it.

The web not only provides terrorists with a way to broadcast their demands and spread fear. It also enables them to monitor their enemies’ reactions while remaining hidden.

From a backroom in Baghdad they can download digital images onto a website, log onto western news bulletins and watch party conference speeches in Bournemouth and Brighton. And all without fear of being easily traced.

It represents a technological advance over Osama Bin Laden’s favoured method of communication during the Afghan war. Videotaping a message and posting the tape to Al-Jazeera, the Qatar-based television station, is now old-generation technology.

JelSoft said it was appalled to find terrorists were using its system and emphasised that they had been doing so without its knowledge or agreement. The software must have been stolen, it said.

Ashely Busby, the firm’s business manager, said: “The appropriate authorities have been informed. We’ll co-operate to shut it down.”

JelSoft said it found out its web services were being used by Bigley’s kidnappers last week when another JelSoft subscriber noticed the company’s logo on one of the kidnappers’ broadcasts.

In theory, the terrorists should be traceable through JelSoft’s web accounts but in reality, the company said, the group had almost certainly stolen the software.

Any attempt to follow the terrorists’ trail would probably end up in a Middle Eastern country where there were few or no laws enabling investigators to continue the digital trace. The most that authorities can do is to try to shut down the website. That happened after the video footage of the beheading of Nick Berg, the US hostage, in May.

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