Bombs hit London's transport network

Bombs have exploded on three London Underground trains and a bus during the morning rush hour, killing dozens of people and injuring around 700.

The attacks took place on 7 July, the day after London was chosen to host the 2012 Olympic Games.

The attacks

Three bombs went off at around 8.50am on Underground trains near Aldgate, Edgware Road and between King's Cross and Russell Square. About an hour later, a fourth bomb exploded on a number 30 double-decker bus in Tavistock Square.

Emergency services worked for hours to rescue passengers trapped in the tunnels, many of them deep underground. Hospitals across London treated hundreds of people.

The entire Underground network was shut down, and buses in central London were suspended. Mobile phone networks were overwhelmed as people tried to contact friends and family.

Terrorism

The Prime Minister, Tony Blair, said it was reasonably clear that the attacks were an act of terrorism. He returned to London from the G8 summit at Gleneagles in Scotland, where world leaders were meeting.

Blair said those responsible were trying to use slaughter of innocent people to cow us, and that they would not succeed.

A group claiming links to al-Qaeda has posted a claim of responsibility on the internet, but police say they are still investigating.

The investigation

Police have launched a major investigation and are appealing for witnesses and for any photographs or video taken by the public.

Resilience

Londoners have been praised for their calm response. The Mayor of London, Ken Livingstone, speaking from Singapore, where he had been for the Olympic decision, said the attackers would not divide the city.

The Queen said the atrocities had shocked the nation.

Security across Britain

Security has been increased on public transport across the country, including in Birmingham. Police have urged the public to be vigilant but not alarmed.

After the Olympic celebrations

The attacks came less than 24 hours after crowds in Trafalgar Square celebrated London's victory over Paris in the race to host the 2012 Olympics.

A minute's silence is expected to be held in the coming days in memory of those who died.