Bombers left a trail of carnage across central London today as the capital became the front line in the war against terror.

Four huge bombs left people dead, dying and horribly maimed in a "barbaric" series of co-ordinated no warning attacks on the city's transport network.

Tonight the toll looked set to rise as one police source indicated that 41 people had perished and 95 were seriously injured.

Scotland Yard officially confirmed that at least 37 people were killed and there were 700 casualties, 300 of whom were taken to hospital by ambulance.

Death and destruction rolled across central London in 60 terrifying minutes as world leaders sat down to business in Scotland at the G8 summit.

Seven people died in the first blast in a Tube tunnel 100 yards from Liverpool Street Station, 21 died in a blast at between King's Cross and Russell Square and seven died at Edgware Road station in an explosion involving three trains.

Exactly 30 minutes after the Edgware Road blast, a bomb tore the roof off a red number 30 double decker bus packed with commuters forced above ground after the Tube network had been shut down.

Scotland Yard said two people were confirmed dead in the bus blast but eyewitnesses spoke of seeing more bodies.

Tony Blair learned of the devastation minutes after holding a joint news conference with his partner in the war on terror President George Bush.

After staging a show of unity with all those leaders present at the summit, he flew back to London to take charge of the crisis.

Tonight Mr Blair pledged that Britain would not be intimidated by the terrorists and promised intense police and security service action to bring the bombers to justice.

In a televised statement recorded in Downing Street, Mr Blair said: "It is through terrorism that the people that have committed these terrible acts express their values and it is right at this moment that we demonstrate ours.

"I think we all know what they are trying to do.

"They are trying to use the slaughter of innocent people to cow us, to frighten us out of doing the things that we want to do, trying to stop us from going about our business as normal, as we are entitled to do and they should not and they must not succeed.

"When they try to intimidate us, we will not be intimidated. When they seek to change our country or our way of life by these methods, we will not be changed."

He added: "The purpose of terrorism is just that. It is to terrorise people and we will not be terrorised.

"This is a very sad day for the British people but we will hold true to the British way of life."