The attacks on London, Part One: The arrests

Caught: how the police got their men

But the arrest of all five bomb suspects was not down to hi-tech surveillance gizmos or futuristic weaponry, according to the head of the Metropolitan Police. It was about "good old-fashioned detective work".

And that is, indeed, the hidden story of an extraordinary week: how detectives working on tip-offs from the public, combing through the records and interviewing people in the street, just as they do on The Bill, tracked down the alleged terrorists. And when they found them, these men did not have the air of satanic glamour lent to them by those fuzzy, chilling CCTV grabs. They were ordinary looking, and they were captured in ordinary places, still living among us.

The first breakthrough came on 22 July, the day after four unexploded bombs were left in rucksacks at Warren Street, Shepherd's Bush and Oval stations and on a No 26 bus. The parents of Muktar Said Ibrahim looked at the CCTV images of the four suspects and realised that one of them, the alleged bus bomber, was their son. He lived apart from them, and had done for a while. They called the police.

The 27-year-old British Eritrean shared a flat in New Southgate, north London, with another suspect: Yasin Hassan Omar, 24, a Somalian British citizen who is suspected of trying to blow up a train at Warren Street. On the same day that Ibrahim's parents rang the police, a neighbour saw him back near the flat with Omar, acting suspiciously.

The one-bedroom, ninth-floor flat in Curtis House was let in the name of Omar, whose rent was paid by Enfield council. Last Monday the police raided the flat and arrested two men, but neither of them was a bomber. On Tuesday they searched a lock-up nearby, and found chemicals which could have been used to make bombs.

The next breakthrough came in the early hours of Wednesday morning when police raided two addresses in Birmingham and found Omar there. Rather than take the chance of shooting an innocent man dead, as they had a few days earlier, they immobilised him with a Taser stun gun capable of generating 50,000 volts of electricity. The muscles of its victim seize up in excruciating pain, but he can recover within 20 minutes. Omar was taken to Paddington Green high-security police station in London for questioning.

The previous Friday a man had been arrested in Stockwell, south London. Now, late on Wednesday, police returned there to arrest three women at a flat in Blair House. They were held on suspicion of harbouring offenders and taken away, along with three small children. One of the women arrested was Yeshiemebet Girma, the partner of a man the police were still not naming at that point, the fourth bomber whose image had been released. He had been filmed wearing a blue England top and carrying a black rucksack, and been seen running away from Shepherd's Bush Tube station moments after a bomb failed to go off there on 21 July.

This man was Osman Hussain, a 27-year-old Londoner born in Somalia. Or perhaps he was Isaac Hamdi, an Ethiopian. The same man has been known by both names, and his nationality is not yet clear. He had two children with Ms Girma, aged six and two. If he had been at the flat where she lived with her mother in Stockwell since the failed attack he was not there when the police called - because he had already left the country. Hussain had taken the Eurostar train from Waterloo the previous day, bound for Paris. But he was using a mobile telephone that belonged to his brother (or brother-in-law, according to some reports), the owner of an internet café close to Termini railway station in Rome, Italy. So as the days went by, investigators working with Italian phone companies were able to listen to conversations between Hussain and his brother and follow the electronic trail of the mobile from Paris to Milan and on to Rome. They listened and waited to pounce.

There were at least 6,000 police officers on the streets of London and in the Underground last Thursday morning, a week after the failed attacks and three weeks since the devastation of 7 July. Half of those officers were armed. The whole transport system was on high alert, and the Metropolitan Police Commissioner, Sir Ian Blair, said it was very possible that "those at large will strike again" or that another terrorist cell might do so. He was confident they would be caught, but warned: "This is not the B team. These were not the amateurs. They only made one mistake [in failing to detonate their bombs] and we're very, very lucky." Nine people were arrested in two raids on addresses in Tooting on Thursday, but so far the only bomb suspect in custody was Yasin Hassan Omar. He had asked for a translator, and complained of feeling unwell from the after-effects of the Taser. His DNA and fingerprints had been taken, his clothing replaced. There had been halal food, a prayer mat and a Koran for him in the police station; he had been given the opportunity to rest, and to see a solicitor. But there were questions to be asked, by interviewers skilled in psychological techniques. He might even have been shown photographs of the bodies of those who died on 7 July. Did he want to talk?

The net began to close, quietly, on Friday morning. The Scotland Yard firearms unit SO19 met with members of an SAS squadron devoted to fighting terrorism. They were about to launch a joint operation that would make the SAS visible on the streets of London for the first time since the Iranian embassy siege in 1980, although this time it was only giving "technical advice". Detectives had been tipped off by a call from a member of the public that one of the men they wanted was in block K of the Peabody estate in Dalgarno Gardens, North Kensington. This was only a short walk from the Little Wormwood Scrubs recreation ground where a rucksack full of explosives had been found dumped the previous Saturday.

The flat had been watched overnight. Then, on Friday morning, one neighbour saw a man in what looked like a bus driver's blue uniform being brought to the flats. He pointed to the fourth floor of the block and was then led away, with his hands tied behind his back by white plastic. The police were also watching another address in Tavistock Crescent, Notting Hill, less than a mile away. A woman there had seen a van with blacked-out windows in the road outside for a few days.

By 10am there were police officers, some in plain clothes and others in uniform with body armour, carrying rifles and machine guns in the streets near the fashionable market at Portobello Road. They moved in slowly and calmly, and were hardly noticed by some. Kieran Batten, a 32-year-old civil engineer, was working in a hole in the street when armed police appeared. "The police shouted, 'Get out of the hole and get out of the area.'" But Mr Batten didn't. He showed remarkable calm in the face of this sudden alarming disturbance. "I carried on working, really because somebody's house could have been flooded if we had stopped."

The first raid was on Tavistock Crescent. Charlotte Brown, a 16-year-old student, saw police marksmen aiming their guns at the flat below hers. It was occupied by a couple she thought were from Somalia, and their two young children, who were "perfectly normal, very nice neighbours". The teenager was scared, and didn't dare look out of the window, but heard police shouting something about containers in the garden below. Police knocked on the door and told her to leave as soon as possible, and also evacuated more than 100 people from other homes nearby.

"Suddenly, we heard five or six bangs," said Davina Johnson, one of the neighbours. "We were all very frightened and we didn't know what to do."

The sound was the front door of the flat being blown off and CS gas canisters fired inside. A man in a white T-shirt staggered out and was wrestled to the ground by police, who handcuffed him. They arrested 22-year-old Wahbi Mohammed, not one of the suspects whose images had been shown, but a brother of one, and the man believed to have dumped the rucksack at the recreation ground.

At the same time, a column of 12 police cars and vans was driving slowly towards Dalgarno Gardens. From the vehicles emerged heavily armed police officers in body armour, some wearing gas masks, others carrying shields. They moved slowly to the front and rear of the 1930s block, and some began to climb the stairs.

On the third floor, Brian Dempster was at home playing with his children, Callum, five, and Tehya, four, when there was a noise outside. Mr Dempster, 36, said he opened his door to see what was going on but armed police yelled at him to get back inside. "All hell seemed to be breaking loose," he said. "The children were crying and shaking."

Television audiences saw the scene from a different perspective, as a neighbour with a video camera captured extraordinary scenes. They showed a boy coming out on to the balcony just as a policeman in body armour and a helmet, carrying a gun and with a dog on a lead, was hammering on the door of the next flat. The boy appeared to try to stroke the dog, but the policeman urged him to get back and appeared uncertain what to do with the child. Then a young girl appeared. Their father looked out to see what was going on, but disappeared again, leaving the children with the policeman. They and their father were shooed away to safety. The streets down below had been sealed off and locals were streaming away from the scene, some running at gunpoint as armed officers urged them to hurry. Many were worried about being victims of a chemical attack.

Cars burst through the cordons, then spilled men in blue overalls, wearing balaclavas and carrying machine guns. A helicopter hovered overhead as officers crouched on the balcony 20 feet from the flat where they believed the failed bombers to be hiding. Their laser sights were trained on the door.

"Come out, this is the police," they shouted, but whoever was inside was reluctant to emerge. An officer called out to one of the men by name. "Muhammed, come out with your hands up." But nobody came. The police could not know if the flat was booby- trapped. One officer could be heard reassuring the men inside that they would not get hurt, but a few moments later another warning by loud hailer that the police would have to come in by force. They could be heard yelling instruction to the suspects to strip to their underwear, walk out of the flat, turn into the corridor and then stop. But still they did not come. This was a siege.

"Why won't you come out?" a neighbour heard a policeman ask.

"I'm scared," said a voice from within the flat. "How do I know you won't shoot me?"

The reply, according to witnesses, was: "That was a mistake." This was taken to be a reference to the death of Jean Charles de Menezes, shot dead by police at Stockwell station on 22 July.

At 12.08pm there was an explosion. Two police officers had crept up to the front door of the flat, crouching as they went, and attached explosives to it.

"There was a bomb that went off," said Lisa Davis, who was in a neighbouring flat but on the telephone to Sky News giving a running commentary. "'Take your clothes off' is what they are telling him right now. They are asking him does he understand. They keep asking him, 'Is there a reason that you shouldn't leave the flat?'"

The voice of a man calling out Muhammad repeatedly could be heard as Ms Davis spoke, along with the words, "You must do what we say." At 12.20pm the voice shouted a warning and CS gas canisters were fired into the flat.

Across the courtyard in block P, Alan Simpson could see what happened next. "There were more shots, low thuds, and then the two men came out on the balcony. They had shaven heads. They were both burly but they had snot pouring out of their noses. Their eyes were streaming."

The men had dropped their trousers and put their hands in the air. They were naked apart from their underpants.

One of them was Muktar Said Ibrahim. The other was Ramzi Muhammed, caught on CCTV running away from Oval Tube station after his rucksack bomb apparently failed to go off. They had both expected death on 21 July. Instead they were standing in their underwear at gunpoint, overcome with the humiliating effects of gas, naked and defenceless, and watched by television viewers all over the country.

The pair walked slowly along the balcony to police, who gave them white paper suits to wear. Eventually they were led away clad in these overalls and in gloves, their faces hidden from the cameras by boards held up by police officers, who themselves were wearing hoods in order to disguise their identities. Explosives experts and forensic officers entered the building an hour after the arrests.

The final drama of Friday afternoon happened several thousand miles away in Rome. There the brother of Osman Hussain had been approached by the Italian security forces and had handed over the keys to the flat where the suspect was hiding, according to an officer involved in the arrest. "Osman was there, immediately in the first room on the right," the anonymous officer said. "He did not put up any resistance. He obeyed all our orders."

Hussain was apparently holding the telephone by which he had been traced, when 40 Italian Central Security Operations officers arrived at the two-bedroomed flat in the Tor Pignattara area of southern Rome. He was brought out of the flat with a black hood over his head. Computers and software were taken away, as they were from the internet café at Termini station, but no explosives were found.

Hussain is expected to be extradited from Italy. He was the last of the five suspects to be arrested. The operation cost more than £4.5m. It involved the police following up 5,000 tip-offs from members of the public, taking 1,800 witness statements and examining 15,000 CCTV tapes. There were at least 29 arrests, in southern England and the Midlands. And yet the search is still not over.

The four failed bombers, and those who died on 7 July, could not have been acting alone. They must have been advised, encouraged, inspired by others who knew about explosives, who could plan the attacks, and had the words and ideas to capture the hearts and souls of young British men.

"It would be a mistake to think we are at the end of this," said a Scotland Yard source on Friday night, despite the remarkable successes of the day. "We might just be at the beginning."

Osman Hussain, 27

Shepherd's Bush Tube bomb

Known to his friends as Andrew, Hussein is originally from Somalia, but is now a naturalised UK citizen. He was seen on CCTV footage running from Shepherd's Bush Tube station wearing a blue England football top, which he later discarded. He fled down the Hammersmith & City line then ran through gardens and a house before boarding a bus towards Wandsworth. He was arrested in Rome on Friday after police traced his mobile phone calls, and will be extradited to Britain. His wife was arrested at a Stockwell flat, and a woman friend was arrested in Tooting.

Ramzi Mohammed, age unknown

Oval Tube bomb

Caught on CCTV after his bomb failed to go off between Oval and Stockwell stations, wearing a New York sweatshirt. Members of the public tried to apprehend him after smoke came from his rucksack, but he escaped and ran through the streets towards Brixton. He is believed to be of East African origin. Neighbours say he drives a No 7 bus, which is based at Westbourne Park station in west London and runs from East Acton to Russell Square. He was detained with Muktar Said Ibrahim on Friday in a flat in North Kensington after a one-hour siege.

Muktar Said Ibrahim, 27

No 26 Hackney bus bomb

Ibrahim arrived in the UK from Eritrea in 1992, aged 14, and was given a British passport last September. He is known to have attended the controversial Finsbury Park Mosque in North London, in which the radical cleric Abu Hamza preached. He is also believed to have befriended the "shoe-bomber" Richard Reid. He shared a flat with the Warren Street bomber Yasin Hassan Omar and joined in Sunday football matches with Omar against teams of boys from their estate. In 1996, he was sentenced to five years in jail for a violent mugging.

Yasin Hassan Omar, 24

Warren Street Tube bomb

The first of the 21 July bombers to be caught, Omar was arrested in Birmingham last Wednesday after police shot him with a Taser stun gun. Originally from Somalia, he arrived in Britain in 1992, aged 11, with his sister. He was put into the care of foster parents. He played football with neighbours in between prayers at the Finsbury Park Mosque and shared a flat with Muktar Said Ibrahim. After his arrest, a local Muslim shopkeeper said Omar had berated him for selling alcohol, and claimed: "Two days after September 11 he was coming into my shop and praising Bin Laden."