The normally busy roads around the City of London are eerily quiet.
By Brian Wheeler
BBC News reporter, Liverpool Street
Every few minutes an ambulance or police car speeds by with its sirens blaring.
But there is no sense of panic among City workers, who are trying to go about their business as normal. The mood is resigned, if anything.
Work has not ground to a halt. Some workers have been evacuated from their offices around Aldgate tube station and the streets have been sealed off
with police tape.
Police officers are standing on every street corner turning people back.
But the crowds which had initially gathered near the station entrances have mostly dispersed.
People travelling into work by train were initially told there was an electrical problem. The first many of them heard that something had happened was when they saw television reports as they emerged from the stations.
At that stage most thought it was a transport problem and were more concerned about how to get to work.
But rumours of what might have happened immediately began circulating. All police would say was that there had been a number of incidents. It was about an hour before the first mention of explosions.
The mobile phone networks stopped working,
with some officials saying they had been turned off for security reasons.
Queues began forming at pay phones as people tried to contact their loved ones.
Karen Daniels, an insurance worker from Walthamstow, said she had walked from Bethnal Green tube station to Liverpool Street after her train was evacuated.
She said: "At first we got on a bus then we were told to get off it. The buses were all informed to turn around.
"I am trying to get to St Paul's, but I might go home. My life is more important than work."
Gaye Flexen, 31, a PA, said: "I was stuck on a tube train for an hour. They told us it was some electrical problem. I just thought it was a typical tube mishap. I got out of the station and saw what had happened
on the TV. I was shocked."
Robert Dewen, a 24-year-old insurance company worker, said: "I saw it on a TV screen when I got off at Liverpool Street. My first thought was
it's Madrid all over again My mum and dad were leaving Aldgate station when the blast went off. They thought it was just work going on in the
"The mood in the office is pretty sombre. Loads of people have been trying to contact us to see if we are OK.
"We have been told the stations are not open. I think we will stay with friends in London tonight."