Security tight as the capital remembers its 'dark hour'

A national two-minute silence will be held at noon as part of a day of events being staged in memory of the 52 people who died in the four bombings; hundreds more were injured. Tessa Jowell, the Culture Secretary, who is responsible for organising today's events, said the attacks were a "dark hour in our history".

Although there are not believed to be any specific threats, security throughout London is expected to be tight, with a visible police presence around Underground, train and bus stations, largely to reassure the public.

Today's events will begin with Ms Jowell, Ken Livingstone, the Mayor of London, and other dignitaries laying flowers at King's Cross station just before 9am, to coincide with the timing of the attacks. Mr Livingstone and others will later lay flowers in Tavistock Square, a year to the minute after a bomb exploded on a No 30 bus.

Plaques carrying the names of all those who died in the explosions will be unveiled at King's Cross, Russell Square, Edgware Road and Aldgate Tube stations, and at Tavistock Square.

Many of the relatives will also attend private ceremonies at St Ethelburga's church in the City of London and at the Museum of London, where a book of tributes, containing the life stories of some victims, will be deposited.

The public will be encouraged to place flowers to help create a remembrance mosaic in Regent's Park, which will be completed at a commemoration service in the evening. At the service, there will be a reading of the names of the 52 victims by Peter Donaldson, the BBC radio newsreader. There will also be a performance by the London Gospel Choir and Trydydd, a group of singers from London, will perform a song written by the family of Helen Jones, one of those who died on the Piccadilly line train.