Apocalyptic: Bigger than 7/7? Worse than 9/11? Piece by piece, the plot unravels

From Pakistan to London, from Whitehall to the White House, the story is of an al-Qa'ida 'spectacular' not just in the air but on British soil, too. It is one of 'dozens' of plots involving 'hundreds' more suspects. Our specialist writers sift the evidence

Few British Home Secretaries in history can have been keeping as huge a secret as John Reid when he gave a speech at Demos, a London think tank, on Wednesday.

There is no question that the Home Secretary knew of the alleged conspiracy to blow up as many as a dozen airliners over American soil, possibly on the fifth anniversary next month of the 9/11 attacks in the US. For months the security authorities here, in Pakistan and the US had been tracking the evolution of a plan to send suicide bombers in pairs aboard aircraft flying from Britain to American cities.

Each bomber would have carried aboard an innocuous-seeming liquid, disguised in a soft-drink bottle, which could be combined in flight into a lethal binary explosive, triggered by an electronic device such as an iPod music player.

If it is true that there was a conspiracy to blow up airliners in waves, three hours apart, the carnage could have rivalled that of September 2001. But in the 100 days since he moved to the Home Office, Mr Reid would have been made aware that the threat went far wider even than that, encompassing the possibility of mass casualty attacks on British soil. The Independent on Sunday was told that "apocalyptic amounts" of explosives, plus some weapons, have been identified as a result of investigations into the current plot as well as previous terror attacks - both those carried out, such as last year's 7/7 bombings in London, and those that have been thwarted.

For months, intelligence reports have been circulating in Whitehall which warn of Islamist terror cells, based mainly in east London, intent on carrying out a so-called "spectacular". There has been a number of unreported arrests of alleged "Islamists" in the area, which are understood to have exposed links between British-born Muslims and terror training camps in Pakistan, as well as to explosives and firearms use. At least one known radical Islamist, who is already under close scrutiny by the police, is also said to be associated with the "east London network".

A Whitehall source said: "This plot was one of many dozens that we are investigating, and that's the frightening thing." Between last July's bombings and the end of 2005, three other terror plots had been thwarted. "There are hundreds of people involved who we are trying to watch." The authorities estimate that there are some 1,200 people in this country "actively involved" with terrorism.

This must have been on Mr Reid's mind when he rose to speak on Wednesday, because an audience expecting him to discuss border controls received instead a stark warning on terrorism. "Let us have no doubt that we are probably in the most sustained period of severe threat since the end of the Second World War," he said. He sometimes felt the courts, as well as critics of the Government's anti-terror policies in opposition parties and the media, "just don't get it". He concluded: "We cannot afford any misunderstanding, in any quarter, about the nature and scope of the threat which we are facing."

Dramatic though his words were, there seemed no reason at the time to believe they related to an imminent threat. Tony Blair, after all, had gone on holiday after wrestling with the issue swamping the headlines, the Middle East conflict. Was Mr Reid aware when he spoke that inside 24 hours, thousands of policemen would be staging raids and arrests across England, airports would be in chaos as flights were cancelled and passengers were banned from carrying liquids, and Paul Stephenson, the Deputy Commissioner of the Metropolitan Police, would be announcing the disruption of a plot "intended to be mass murder on an unimaginable scale"?

It is unusual for so much detail to emerge so quickly about a planned act of terror that was never carried out. Within hours of Thursday's security swoop, we knew the alleged target and method of attack. By contrast, the sequence of events which led to the alert has become mired in ever-increasing confusion.

On Saturday a grainy photograph of a heavily bearded man appeared in every British newspaper. Most of them said the picture was of Rashid Rauf, a 29-year-old Birmingham-born British citizen recently arrested in Pakistan. Others said it was of Matiur Rehman, a high-ranking al-Qa'ida operative believed to have been plotting attacks on the US. One newspaper suggested Rehman and Rauf were one and the same man, but that has been dismissed by officials both in Britain and Pakistan.

Rehman, a Pakistani in his mid-30s, he has been identified as al-Qa'ida's planning director, and was quickly linked by officials in Pakistan with the UK plot. They believe he may have been contacted by Rauf, whose 22-year-old brother Tayib was arrested in Birmingham early Thursday.

It was the arrest of Rashid Rauf about a week to 10 days ago that triggered the security operation in Britain last week, according to accounts in Pakistan. After he disappeared from contact, a panicking fellow conspirator telephoned the UK to tell the bombers to bring the plot forward and go ahead immediately after Mr Rauf disappeared from contact. The call was intercepted, and the British police mounted an emergency operation to stop the bombers.

The British authorities have been at pains to point out, however, that this was the culmination of a surveillance operation lasting several months. British security received the tip-off that led to the uncovering of last week's terror plot after the suicide bombings of July 2005. A call was made to MI5's hotline from a concerned member of the Muslim community, reporting general suspicions about an acquaintance. MI5 began to look into one individual and gradually realised that it had something big on its hands.

From that morsel of information, according to a senior French intelligence official, British authorities opened the investigation into what they said turned out to be a well-organised plot to bomb transatlantic flights. "It's not like three weeks ago all of a sudden MI5 knew about this plot and went to work," said a US law enforcement official. "They'd had a concern about these guys for some time - for months. Details started to emerge, and it became clear over the last couple of weeks the nature of the threat and the individuals."

By the end of the year a major case conference by the security agencies was held in which it was decided to mount an unprecedented surveillance operation. The growing number of suspects in the cell was to be followed by crack MI5 surveillance teams. Some of the cell's members had been well trained and continuously used anti-surveillance techniques, such as driving round roundabouts twice, and going back on themselves.

MI5 worked closely with anti-terrorist police and more than 50 people were placed under surveillance. They later focused on two dozen suspects, and a dozen vehicles fitted with GPS tracking devices. Agents began tracking calls from mobiles and public pay phones, and monitored emails to Pakistan, Iran and Europe.

GCHQ was monitoring the suspects' phone, mobile, text and email transmissions, as well as their use of the internet.

"The difference between this lot and the 7 July people is that after 7 July we had a blank sheet of paper. We had to build up pictures of their lives," said a Whitehall source.

"Here, MI5 knew an awful lot about the individuals concerned as we had been watching them for months."

Security officials from the US and Pakistan said they were briefed by their British counterparts late last year. By early 2006 the investigation had ballooned to involve several hundred investigators on three continents. They kept dozens of suspects under close surveillance for months, even as some of the plotters travelled between Britain and Pakistan to raise money and get expertise, according to interviews with US and European counterterrorism officials.

By March MI5 told police a major attack was being planned. Suspects were monitored inquiring about flight prices for a dozen American destinations. Twelve went to the US embassy in Grosvenor Square to obtain their visitor visas. MI5 alerted the FBI.

A law enforcement bulletin issued on Thursday by the US Department of Homeland Security and the FBI described the conspiracy as "international in scope". "This plot appears to have been well planned and well advanced and in the final stages of preparation," the bulletin stated.

Investigators believe the operation was composed of three distinct cells, whose members may not have been aware of the others or the extent of their assignment, American officials said. The puzzle was how exactly the plotters were planning to commit the outrage. But then MI5 had a breakthrough from one of its sources.

"MI5 alone cracked the modus operandi of the plotters, and with the help of the police, that's where we are now," said a Whitehall source. "What they had done was effectively and cleverly to find a way to get an IED [improvised explosive device] on board an airliner without being detected."

By the end of July, teams had covertly monitored suspects buying chemicals and laboratory glassware by mail order. The bomb components would be disguised as everyday objects and assembled as a device on board. The IED would be exploded over the Atlantic.

"It's fair to say they were aiming for multiple flights, and some of the exact data of who they would deploy, and how many might be in one deployment, are somewhat ambiguous," said Michael P Jackson, the deputy secretary at the Department of Homeland Security. "The real focus was to blow up airliners and the people on them," he added.

The belief was that the conspirators might be timing their "spectacular" to coincide with the fifth anniversary of the 11 September 2001 attacks. British and US authorities decided against breaking up the cells right away, in the hope that they could learn more about the origins of the network and assemble evidence for prosecutors.

Originally the plan had been to let the plot run longer through August. Tony Blair went on holiday, believing that the arrests were not imminent. But something - perhaps the arrest of Rashid Rauf - led to a rapid change of plan.

"On Wednesday the intelligence we received from various sources suggested that the threat to public safety had suddenly become imminent, and an attack was likely in the near future. Then came the executive decision to launch the police raids," said the Whitehall source.

The Prime Minister was not the only key figure away from his desk. On Monday Douglas Alexander, the Transport Secretary, was relaxing in his holiday cottage on the isle of Mull, off the west coast of Scotland, when he received an urgent phone call from officials in his department. They told him they needed to give him a message that was so sensitive it could not be communicated by phone, and a official with the highest security clearance was flown from London to speak to the cabinet minister. For the first time Mr Alexander learned of the plot.

The minister was given the option of remaining in Mull or coming to London to help to co-ordinate the security operation, which would not only have serious implications for thousands of air passengers, but also would lead to the stepping up of security at airports in Britain, the US and beyond. Mr Alexander at first decided to remain on the island and remain in contact by phone. But on Wednesday, an RAF helicopter landed in his back garden to whisk him away to the capital.

By that time Mr Blair had left for Barbados. The previous Sunday, he spoke to George Bush about the surveillance operation, and is believed to have told him there was a threat to US airlines and travellers. On Monday Mr Reid and Mr Alexander received fresh intelligence briefings, and were told the operation was nearing its critical final phase.

The next day, with the Prime Minister on his way to the Caribbean, his Home Secretary gave his speech to Demos. According to the think tank, it was arranged more hastily than usual, and the topic was altered at even shorter notice. While Mr Reid's allies dismiss this as a normal occurrence, others believe that he was deliberately capitalising on inside knowledge that a major terror raid was about to occur.

During the early part of last week there were several meetings of Cobra - the Cabinet Office Briefing Room A - which co-ordinates major national emergencies. It was Wednesday's gathering, chaired by Mr Reid, which decided to launch the arrests.

On Wednesday evening, as senior officials were heading home, they received calls on their mobile phones, telling them to return immediately to Whitehall. They were made aware that something big was up, but they could not be given any details over insecure phone lines. Instead they were ordered to head straight to the Home Office's Marsham Street headquarters: the glass-fronted building had become the nerve centre of what had become a major anti-terrorist operation.

Gathered there were not only senior Home Office and Transport Department staff, but also senior police officers and security officials, including Dame Eliza Manningham-Buller, director-general of MI5. She was personally briefing Mr Reid on what was to become one of the biggest anti-terror operations ever seen in Britain.

The formal Cobra meeting which began at 9.30pm was the first of three that night. After the politicians were briefed on the police raids, the discussion turned to how to handle the disruption to the transport system and the economy.

The meeting broke up at 10.30pm, just as hundreds of police were preparing for the first of the raids, which began at midnight. It was the beginning of a long night for Mr Reid, in which he gained only a few minutes' sleep. Mr Blair spoke by phone from Barbados to John Prescott and Mr Reid, then called Mr Bush at his ranch in Texas to brief him fully. Back in London the Home Secretary made phone calls to colleagues and his counterparts in the United States. At 4am on Thursday he spoke to Gordon Brown, at home in Scotland with his new baby, about the implications for the economy. The Chancellor then began to set in train moves to freeze the bank accounts of any suspects.

At 5am another Cobra meeting discussed how to handle the media and damage to the economy. It was agreed that Mr Reid would brief the Tories and Liberal Democrats, while Mr Prescott took on the job of speaking to constituency MPs.

As Britain woke up to the news on Thursday, and thousands of holidaymakers began arriving at airports to discover total disruption, one of the first questions was whether the plot was connected to al-Qa'ida. In many other terrorist conspiracies, such as the 7/7 bombings in London, the link took time to emerge. This time security sources were in no doubt.

A Whitehall source said that the plotters had been in touch with al-Qa'ida in Pakistan: "There is a Pakistani link. My view would be that there are links to al-Qa'ida."

Another intelligence source said: "The ringleaders of the plot had clearly made connections in Pakistan with people who can only be described as al-Qa'ida. The UK people were provided certainly with expertise, if not more."

Pakistani officials have also drawn a clear connection to al-Qa'ida. The interior minister, Aftab Sherpao, described Rashid Rauf as "an al-Qa'ida operative", although he added that Mr Rauf's "linkages" to the network were in Afghanistan. He also claimed that the Briton had been arrested near the Afghan border, when most other reports say he was held in Karachi, Pakistan's biggest city.

Mr Sherpao's words were seen as an effort to deflect attention from Pakistan's connections to al-Qa'ida, which others describe as strong. Despite officials' description of the plot as "Afghanistan-based", there are signs of links to Pakistani militant groups, including Lashkar-i Jhangvi, which was involved in the murder of the American journalist Daniel Pearl. A video of his gruesome beheading was posted on the internet.

Lashkar-i Jhangvi is considered very close to al-Qa'ida. Another Pakistani group, Lashkar-e-Toiba, which operates mainly in Indian-held Kashmir, is also being examined for links to the plot. Pakistani officials also say they are investigating possible links to two British groups, Hizb ut- Tahrir and al-Muhajiroun, which have been banned in several countries.

The Pakistani authorities have also been examining money transfers connected with the plot. Pakistan's Daily Times newspaper reported yesterday that what first alerted intelligence agencies to the Pakistani side of the plot was the transfer of huge sums of money from the UK to three men in Pakistan, two of them British, disguised as donations for Kashmir earthquake relief work. According to the Pakistani newspaper, it was the British who first noticed this and alerted the Pakistanis.

What triggered alarm was that a Muslim charity based in Britain had transferred the money directly to the private bank accounts of three individuals, not to any organisation. Two of the men are British citizens of Kashmiri origin; the third is a Pakistani builder from Kashmir. All three have been arrested - one appears to be Rashid Rauf, but the other Briton has not been named.

Pakistan has also pointed to the possible involvement of Matiur Rehman, a senior militant who has been described as a rising leader within al-Qa'ida. Mr Rehman, who is believed to be still at large, is suspected of being behind at least one of the assassination attempts on President Pervez Musharraf. He also has links to Lashkar-i Jhangvi, one of the groups Mr Rehman is being investigated for links to.

Pakistan is home to a myriad of different militant Islamic factions, and they often co-operate - one of the methods encouraged by al-Qa'ida. At least four different groups are believed to have been involved in the Daniel Pearl kidnapping and beheading.

American law enforcement sources have said that Mr Rehman is now the "leading suspect" in the attack earlier this year on the US consulate in Karachi that killed a State Department Foreign Service officer, David Foy. Officials say the car bomb attack was planned by Mr Rehman.

The officials say Mr Rehman was spotted within the past month in the slums of north Karachi but escaped capture. The Pakistani government has posted a reward of 10 million rupees for the capture of Mr Rehman, who also uses the aliases "Saddam Sial "and "Akeel Khan".

Mr Rehman, along with his deputy, another Pakistani named Hassan, are believed to be keepers of the "Directory of Jihad", which Pakistani officials claim contains hundred s if not thousands of names of young militants who trained at al-Qa'ida camps.

Mr Rehman, thought to be 34, worked as an explosives instructor in the al-Qa'ida camps. Pakistani security officials say he has been deeply involved in most of the major terror attacks in Pakistan in the past few years.

Former French counterterrorism official Alexis Debat who first identified Mr Rehman to the West, says that he moves between Karachi, Waziristan and south Punjab, where he was born. He is in "constant communication" with al-Qa'ida's top leaders, according to the officials.

The question of whether Osama bin Laden still maintains control over active terrorist operations around the world is one of constant debate and analysis within the US intelligence community. He has made frequent statements on audiotapes distributed over the internet, and his deputy Ayman al-Zawahiri appeared in a videotape as recently as last month. Both claim to lead a widespread movement, involved in virtually every Islamic battle from Iraq to Indonesia, that is building an anti-Western "caliphate" across the world.

All this helps explain why Pakistani officials are so keen to claim credit for helping to foil this terrorist plot. British officials make clear that there was indeed good co-operation, and Mr Reid made a point of thanking Pakistan in public. But the country is still open to the charge that it has done too little to curb militant Islam.

"Al-Qa'ida has been Pakistanised, if you will," said M J Gohel of the Asia-Pacific Foundation, a London security think tank.

The Pakistan Connection: 'Mastermind' named in police poster

The Pakistani authorities last night released a "wanted poster" of Matiur Rehman, the man alleged to have masterminded the plot exposed last week to plant liquid explosives on trans-Atlantic jets.

Rehman is accused of being linked with a Briton and key suspect arrested in a border area of Pakistan earlier this month, Rashid Rauf, from Birmingham, whose detention apparently sparked off Thursday's early morning raids in the UK.

Pakistani security officials say Rehman was spotted within the last month in the slums of the southern city of Karachi but escaped capture. The authorities have now offered a substantial reward of 10 million rupees (£87,000) for his capture.

Operating under the pseudonyms "Samad" or "Saddam Sial", Rehman, from Multan in the Punjab, is the second-in-command to an alleged al-Qa'ida ring-leader in Pakistan, Amjad Hussain, alias "Amjad Farooqi".

Severin Carrell and Paul Lashmar

Who knew what when? When did Blair know of terror raids?

Officially Tony Blair went on holiday on Tuesday unaware that the terror raid was about to go ahead. Yet two days earlier he informed George Bush that a UK cell had been under surveillance since last year and that there was a direct threat to US airlines. The question now being asked is why he chose to inform the President then and whether he went to Barbados knowing that within days Britain would be subject to the biggest terror alert since 7/7. On Wednesday, the Home Secretary warned of a new breed of "unconstrained international terrorists". At the last minute, the subject of his speech was changed from border control to terror. Questions are also being asked about whether US Republicans had been alerted by the UK. Dick Cheney spoke on Wednesday about the al-Qa'ida terrorist threat. The White House later admitted that he had known about the UK terror plot, but not that raids were imminent.

Marie Woolf

TECHNIQUES OF THE TERRORISTS

* Liquid bomb An al-Qa'ida cell in the Philippines tried to develop liquid bombs to bring down 12 planes flying to the US in 1995.

* Shoe bomb The British Muslim convert Richard Reid is serving life for trying to detonate a bomb hidden in his trainer in 2001.

* Dirty bomb Al-Qa'ida has allegedly tried to make a bomb to contaminate cities with radioactivity.

* Fertiliser bomb Large amounts of agricultural fertiliser are mixed with ammonium nitrate to create massive bombs.

* Hijacking Used to devastating effect on 9/11, when al-Qa'ida cells brought down four planes, killing 2,973 people.

* Rucksack bombs Al-Qa'ida-linked cells used crude homemade bombs hidden in luggage to kill 52 people on trains and buses in London, and 192 in Madrid.