Tears and prayers on the day a city remembered its dead

At 8.50am, as her Piccadilly line train rattled between King's Cross and Russell Square, Rita Shah joined her hands together, closed her eyes and prayed.

It was at the same moment and the same place that, 12 months ago, Germaine Lindsay, one of the four bombers on July 7, detonated his device and murdered 26 people. But for one of those random quirks of fate ­ for once she took a different route to work that morning ­ it is likely Mrs Shah would have been on the same train that was turned into the charnel house of a suicide bomber. Her prayer was one among myriad private acts of remembrance taking place yesterday.

At King's Cross, a male commuter was comforted by station staff as he found himself in tears at the Tube entrance, unable to go any further. Other staff accompanied family members to platforms where their loved ones had boarded the trains.

This was the backdrop to the official commemorations of the attacks that killed 52 people and injured more than 700. Victims and relatives stood with the rest of the nation at midday for a two-minute silence to commemorate the dead and honour the survivors.

Mrs Shah, 37, who got off at Russell Square, said: "Today is a very difficult day. I changed the way I got to work that day last year. Otherwise I could have been on the same train and carriage. I normally travel on this line at this time. I just said a prayer to mark what happened. In my office, I lost two colleagues on 7 July. It was a terrible day, but I'm grateful to be here to remember them."

Transport for London insisted that the number of passengers on the Tube and bus networks was much the same as a normal Friday. But near-deserted carriages during rush hour at interchanges such as Victoria, Oxford Circus and King's Cross, where the four bombers reached London after a journey from Luton, indicated that the emotions of that day remain raw despite a heavy police presence around stations.

Waiting for a Victoria line train, Peter Furlong, 45, a civil servant, from Stockwell, said: "I think a lot of people are apprehensive. Even if, like me, you weren't directly affected, most Londoners will have gone to work today with a feeling of sorrow and a little anxiety that it could happen again."

Above ground, a set of ceremonies provided the public outlet of the capital's grief, culminating in an open-air event at Regent's Park yesterday evening.

Ken Livingstone, the Mayor of London, led the early commemorations by laying wreaths at King's Cross at 8.50am and then at Tavistock Square at 9.47am to coincide with the explosions on three Tube trains and a No 30 bus. Mr Livingstone said: "The bombers wanted to shatter what London has become, because it stands for everything they are opposed to. It is the world's most international and tolerant city. They wanted to shatter that. Instead they saw Londoners of every race and creed come out in common grief, solidarity and humanity."

Tony Blair, who observed the two-minute silence at the London Fire Brigade's headquarters, said: "This is a time when our country unites across all races, religions and divides and stands in solidarity with all those who have suffered so much, in sympathy with them and in defence of the values which we share."

Memorial plaques were unveiled at each of the locations where the bombers struck: Edgware Road, Aldgate and Russell Square Tube stations, where Mohammad Sidique Khan, Shahzad Tanweer and Lindsay detonated their bombs, and Tavistock Square, where Hasib Hussain blew up his rucksack bomb on the No 30 bus.

They were events devoid of the chaos of 12 months ago but no less filled with shock, while others in surrounding streets went about their lives.

At Tavistock Square, the plaque unveiling took place behind black screens to protect the privacy of relatives. Outside, people wept as church bells marked the start of a two-minute silence.

At Edgware Road, where Khan killed six people, relatives and survivors carried floral tributes. Among them was Susannah Pall, 25, a City broker who was on board the Circle line train and returned to the station for the first time yesterday.

She said: "I've been building up to this day. I was going to stay away but decided to come. Until I do it, I can't move on." Grieving families joined the Prime Minister and other politicians in Regent's Park in the evening for a service of readings, poems and songs.

Amid the remembrance there was a grim warning that it could all happen again. Sir Ian Blair, the Commissioner of the Metropolitan Police, said: "Since July the threat has palpably increased, and I fear that we have to accept that we live in an age when the threat of an attack getting through is very real."

Even so, al-Qa'ida's attempt to twist the first anniversary to its own purposes by releasing a video of Tanweer was ignored. Instead, it was a day for terrible memory. John Falding was talking to his girlfriend, Anat Rosenberg, on her mobile when she was killed at Tavistock Square.

Mr Falding said: "Last night I found I was looking at every single minute and thinking what we were doing exactly a year ago when we went to the open-air theatre in Regent's Park ­ now would have been the interval, now would have been the time we were having a drink. It carried on this morning: just every aspect of a year ago came back to me, and I watched the clock go down to 9.47am and I felt I had lost her again."