Across the world to train for their murderous missions

Key points

• Details emerge of links between London suicide bombers and Pakistan

• Intelligence officers believe terrorists trained in schools known as madrassas

• UK Government has ruled out any public enquiry into why threat not known

Key quote

"We are trying to establish if they had any links with those involved in the London blasts" - INTELLIGENCE OFFICIAL

Story in full THE full extent of the links between the London suicide bombers and Pakistani terrorist groups was emerging last night, raising fresh questions about how the plot was allowed to go undetected for so long.

A week after The Scotsman first revealed the suspected link between the bombers and al-Qaeda-related groups in Pakistan, intelligence services there released pictures of three of the men - including Mohammed Sidique Khan, the suspected ringleader - arriving in Karachi for extended stays.

The men are believed to have spent months meeting terrorist groups and receiving tuition at their associated religious schools. A list of 20 other Britons is said to have been passed to the Pakistani authorities to check out, amid fears that they too may have been through the same process before returning to Britain to prepare for more attacks.

General Pervez Musharraf, the Pakistani president, yesterday conceded that some of the religious schools - known as madrassas - were involved in training terrorists: "Yes, today, some madrassas are involved in extremism and terrorism," he said.

As the death toll from the bombings climbed to 56, Israel also confirmed that Khan had visited the country in 2003, bolstering reports that he had helped plan a suicide bomb attack by two other Britons of Pakistani descent in Tel Aviv. Khan had already been linked to a group involved in another alleged British bomb plot.

The British government has ruled out any public inquiry into how the London plot went undetected, but the question it will now want answered quickly is how one of the world's most sophisticated intelligence networks failed to pick up on the danger signs.

Details are emerging fast as the investigation gathers pace. The Pakistanis now know that Khan and Shehzad Tanweer flew into Karachi airport together at 3:30pm on 19 November, 2004 on Turkish Airlines Flight TK-1056 and departed on the same airline, flight TK-1057, on 8 February this year. They believe that they were met at the airport by four bearded men and left in a car. Checks on hotel records indicate they stayed at a hotel in Saddar for one week before leaving for Lahore by train.

The intelligence officers know that a third bomber, Hasib Hussain, flew into the same airport on a Saudi aircraft four months earlier on 15 July. He passed through the immigration counter at 1:19am.

What the bombers did while they were in Pakistan remains the key to the investigation, but intelligence officers have already said they believe Tanweer visited one madrassa run by the al-Qaeda-linked terrorist organisation Lashkar-e-Taiba and another run by another al-Qaeda-linked group, Jaish-e-Mohammad. They are investigating claims that Tanweer met Osama Nazir, a leading Pakistani terrorist with alleged al-Qaeda links.

Pakistani security services, using their computerised Personal Information Secure Comparison and Evaluation System - installed after the 9/11 attacks to document all arriving passengers at Pakistan's international airports - found that Hussain was the first to enter the country, arriving in Karachi on a British passport, number 300514155, on Saudi Arabian airliner, flight SV-714 in July.

Hussain is believed to have stayed in Pakistan for four months but there is no record of his departure at Karachi airport, suggesting he went back to London either from Lahore or from Islamabad.

Tanweer, passport number 453897014, and Khan, passport number 040169095, arrived in Karachi from Istanbul in November for a three-month stay. Like Hussain, they were photographed at the airport: Khan looking tired, Tanweer looking nervous.

A week after arriving, they left for Lahore by train. Later, they moved on to Faisalabad. At the weekend Pakistani security forces detained five militants as part of a crackdown launched after the London bombings.

"We are trying to establish if they had any links with those involved in the London blasts," an official said. One was Qari Usman, a Jaish-e-Mohammad bomb expert who may have been involved in a plot to kill Mr Musharraf in 2003.

Another intelligence official said other detentions in Faisalabad last week were based on information from Jaish's Osama Nazir, who was arrested in December for a 2002 church bombing and who had told police that he met Tanweer in Faisalabad in 2003.

Shahid Hayyat, a deputy director at the Federal Investigation Agency, said they were now trying to establish what the British bombers did during their stays.

"I know that our security agencies are trying to get such details," he said.

They will want to examine claims that Khan was known to Mohammed Junaid Babar, a Pakistani American with al-Qaeda connections who has admitted setting up terrorist training camps in Afghanistan. Babar has told US authorities that he met Khan in Pakistan.

They are also investigating whether Tanweer and Khan contacted a group led by Abu Faraj al-Libbi, said to be al-Qaeda number three. He was arrested in Pakistan in May.

British police are apparently keen to talk to Zeeshan Siddique, 25, who is being held in Islamabad after being arrested in Peshawar in May. His name has been linked with a British bomb plot and authorities say he is also believed to have attended terrorist training camps. There are also suggestions he met Tanweer.

The security services appear optimistic that there will be further breakthroughs.

The Turkish airline has been asked to help identify the airport from which Tanweer and Khan flew into Istanbul and also to provide details of their onward travel on the return leg.

The madrassas have also been asked to hand over details of foreign students who are studying with them, and officials are concentrating on those with previous links to terrorist groups.

Meanwhile in Britain it emerged that police had found two bombs, a gun and ammunition in the boot of a car left at Luton train station by the bombers.

Last night it emerged the bombers bought their rucksacks in Blacks camping shop in Leeds city centre. The retailer told Channel 4 News it would no longer stock that type of rucksack.