Here is a selection of eyewitness accounts we received from people involved in the explosion at Liverpool Street.
We travelled out into the tunnel and not long after we set out all I saw was yellow light and what appeared to be silver lines in front of my eyes - which turned out to be glass.
I was being twisted and thrown to the ground. I thought I wasn't going to get out of this - whatever it was - I just didn't know. I thought that was it when it went all so dark.
Then I touched my hand to my face and felt the blood and knew it wasn't all over yet.
I am an extremely lucky man, I am very lucky indeed especially as I saw what happened in the next carriage.
The bomb must have been within 10 feet of me but that carriage took most of the blast and we were just showered in glass.
Our carriage was smoke-filled, there was lots of dust, there was lots of panic. We could hear the screams from the carriage where the bomb had gone off - they were trapped in twisted metal.
The doors wouldn't open then we saw this orange jacket which turned out to be one of the drivers. We decided we were going to walk out down the middle of the train.
Everybody was absolutely terrified.
You could hear the screaming from the carriages in front, because that was where the explosion had happened, and there were lots of injured people there.
Nobody knew what was going on.
The driver was trying to communicate with us, but the radio wasn't working.
People were trying to open the doors and the windows to let the smoke out and were rocking the train, which already felt like it had come off its rails.
So we were panicking that the train was going to get knocked over.
It was just general chaos. I thought I was going to die when I saw the flames.
I thought we were going to get engulfed by the flames or get overwhelmed by the smoke.
I really didn't think we were going to get out.
It hasn't quite sunk in, I think.
It's the kind of thing where you see it on the news, but don't expect to be in it. Well, I was in it and it was horrible.
I had to hand in a pair of shoes to a repair shop in Aldgate High Street while walking to the office this morning.
Fire engines were arriving at Aldgate Tube station as I approached it and the guys in the shop said they had felt their building shake and their windows rattled.
It seemed people were lying on the pavement outside of the station although it was difficult to see clearly.
Others arriving in the office reported that staff in the bus station opposite the Tube station had seen smoke coming from the tube station.
I had just got on to the westbound Circle Line train, second rear carriage, at Liverpool St Station.
The explosion seemed to come out of the tunnel leading from Aldgate.
There was dust and smoke in the air.
I thought a bomb had gone off in the rear carriage but couldn't see any damage to it.
Then people started to evacuate quickly after a few moments.
I didn't see any injured people though.
There was no real panic - just a overwhelming sense to get out of the station quickly.
I had just got on tube at Liverpool Street and just before the doors shut, an explosion went off in the next carriage.
Lights went out and people calmly left the tube.
There was smoke coming from the carriage.
On my alternative route to work, I walked up Southampton Row when I heard another explosion and people running in a panic from Russell Square.
I was on the train that the 'bang' happened on.
I must have been two or three carriages down from where it originated.
I would like to praise the people in my carriage and on the train as a whole for remaining calm despite the sense of fear everyone must have felt when this happened.
There was twisted metal from the train laying on the track which we had to pass as well as injured people who needed urgent medical attention
After waiting for maybe 15 minutes or more we were rescued by emergency services and had to walk the remainder of the way down the track to Aldgate station.
There was twisted metal from the train laying on the track which we had to pass as well as injured people who needed urgent medical attention.
The emergency services were doing an excellent job taking care of people and their response in general was superb.
Bravo to them.
I was at the station when the explosion happened.
I had just arrived on the eastbound Circle/District line station at Liverpool Street.
As usual, I walked down to the far left hand side of the platform.
I had only been there for a minute or two when a train pulled up on the other side platform (westbound).
The doors opened and as everyone was starting to get off, I saw a few lights starting to flicker overhead and then there was an explosion on the opposite side to me, just behind the train that had just pulled in.
As you can imagine there were quite a few people panicking and quite a number of people started screaming and running towards the exit.
I had a quick glance behind me as I was leaving and saw some smoke coming from the area where the explosion had happened.
The station was evacuated fairly quickly.
I saw people coming out of Aldgate station covered in soot and blood; some of them clearly in shock.
People were just walking off into the streets with soot and blood on their clothing and faces.
Emergency services were in attendance.
One man told me there had been an explosion on the Circle line and he described it as "horrible down there".