In the aftermath of 9/11 and the US-led invasion of Afghanistan much of al-Qaeda's infrastructure including its training camps were destroyed. Peter Taylor's three part series examines the new al-Qaeda which has emerged and the threat it poses to the West. The first part, jihad.com explores how the internet has become the lifeblood of the new al-Qaeda.
The internet has been key in pulling together the shattered remains of the organisation that operated before the invasion of Afghanistan, according to the general running the Iraq war, Lt Gen John Abizaid.
He says: "The only safe haven that remains for al-Qaeda is the virtual realm. It is one that we all should be worried about."
Mike Sheuer, former head of the CIA Bin Laden unit, agrees: "The current state of al-Qaeda and the health of al-Qaeda is largely due to its ability to manipulate the internet."
Following a year-long investigation, and just over two weeks after the London bomb attacks, BBC reporter and terrorism expert Peter Taylor peers into the murky world of the internet jihadi.
He discovers how bloodthirsty videos are made in Iraq and circulated by webmasters in the UK and elsewhere, in an underground broadcasting network.
He finds the web has become a secret and safe means of communication, as well as an inexhaustible online library of training manuals and information on how to carry out terrorist attacks.
Combined, these elements make the net the most significant weapon in al-Qaeda's new fractured and decentralised state.
This one-hour documentary traces the link between videos from Iraq shown on websites, including beheadings and car bombs, and recruitment of international volunteers joining the insurgents.
Reporter Peter Taylor meets jihadi webmaster Mohammed al-Massari
It challenges the webmaster Mohammed Al-Massari, who runs a website from his home in London and sees nothing wrong with such images being shown on his site.
The programme also explores the story of Babar Ahmad whom US prosecutors accuse of having pioneered al-Qaeda's activities on the internet in the late 1990s from his office at Imperial College in London.
It hears from his associates, among them one whom MI5 repeatedly tried to recruit, and reveals major new information about Ahmad from Pakistani intelligence.
Through unique access to the interrogation of a Pakistani webmaster described as al-Qaeda's leading IT expert, the programme can also reveal the part the web has played in major terror incidents.
And it looks at how British and US security agencies are now using the net to penetrate terrorist operations.
While fears are raised by some that civil liberties are being eroded, one female local magistrate, who uses the anonymity of the net to pass herself off as a radical, has been responsible for the conviction of a Islamic radical.
The New Al-Qaeda: jihad.com was broadcast on Monday 25 July 2005 at 2100BST on BBC Two.
Reporter: Peter Taylor
Assistant producer: Matt Cottingham
Series producer and director: Sandy Smith
Executive producer: Farah Durrani