Britain on Friday remembered the victims of the deadly suicide bombings on its transit system last year which claimed 52 lives, with memorial services, floral tributes and a two-minute silence.
The country fell silent for two-minutes in memory of the victims of the attacks, in which more than 700 people were injured.
Prime Minister Tony Blair, who attended a private memorial at London's Fire Brigade headquarters, said the anniversary was an opportunity for "the whole nation to come together."
He said it was a chance "to offer comfort and support to those who lost loved ones or were injured on that terrible day."
"This is the 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," he said.
The silence was observed at around 4.30 am, signalled by the tolling of the Lutine Bell at the Lloyd's of London insurance market.
The traffic came to a halt, and workers poured out of offices to line the sidewalks in a mark of remembrance and solidarity.
Earlier, flowers were laid at the King's Cross station, the scene of one of the four attacks, at 8.50 am, the precise moment when bombs on three Underground trains went off.
UK Culture Secretary Tessa Jowell and London mayor Ken Livingstone led mourners in placing flowers at the station.