Police are confirming the shooting incident at Stockwell.
It seems that a man jumped the barriers at Stockwell underground station and ran for a Northern Line train.
One witness on BBC News 24 says he saw the man go down and then police shot him five times:
"I was sitting on the train reading my paper. I heard a load of noise, people saying, 'Get out, get down'! I saw an Asian guy run onto the train hotly pursued by three plain-clothes police officers. One of them was carrying a black handgun - it looked like an automatic - they pushed him to the floor, bundled on top of him and unloaded five shots into him. I saw the gun being fired five times into the guy - he's dead."
11.10 Reuters are reporting that armed police have surrounded a Mosque in East London.
11.17 Local residents near the Mosque have been told to stay indoors. Still no precise location although we hear the mosque in question is by Aldgate East.
11.20 The Mosque is on Whitechapel High Street. Police are concerned there could be explosives/suspect packages in the building. Residents are advised to stay indoors.
11.30 Media are awaiting a briefing at Stockwell.
11.33 The incident at the East London Mosque is over. Cordon has been lifted. Looks like it was a false alarm.
11.36 Witness talking to BBC 24 describes a smoking backpack causing panic between stops on the way to Stockwell.
11.42 Downing Street spokesman says Blair is being updated at Chequers.
11.46 Scotland Yard confirm that their men shot dead a man at Stockwell.
12.02 An eyewitness from outside the station tells BBC News 24 that an armed plain clothes police officer jumped across his car. Several other armed policemen then joined the chase down into the tube. Regular police officers seemed as surprised as passers by as this unfolded.
14.22 Police snipers have taken up positions on the Harrow Road which is now cordoned off. There is a "huge police presence" and bomb disposal vehicles on the scene. Those living nearby are again being told to remain indoors (Bravo to the chap ringing up BBC News 24 and name checking Big Trak).
14.55 An Internet cafe on the Harrow Road seems to be the focus of the police attention. Two women are reported to have been removed from the cafe.
15.00 Scotland Yard say no arrests have been made and the armed police are there simply as a precaution while they search an address in realtion to yesterday's incident.
15.08 A witness speaking to BBC News 24 believes she heard six gun shots at the Harrow Road incident, but this has yet to be confirmed. The police say the Harrow Road raid is just one of several unfolding in London today.
15.30 Sir Ian Blair at a press conference praises the police force but calls for understanding and calm. Asks London to concentrate on facts rather than rumours. The focus is on criminals and not communities. He confirms police shot dead a man at Stockwell this morning and that this was linked to yesterday's incidents. His understanding was that the man was challenged and only shot when he refused to co-operate.
A call for help from the public is renewed. CCTV images of the four men involved in yesterday's events will be made available. Firstly anyone who knows where those men are should call 999 immediately. Secondly anyone who recognises the men should call the Anti Terrorist hotline on 0800 789 321.
Besides the Harrow Road address two further London addresses are currently being examined. Initial forensics say that all the bombs yesterday were partially detonated and seem to be home made.
16.05 A witness on BBC News 24 (after she begrudgingly turns off her mobile phone - "You're live on the BBC!") says her house on the Harrow Road was taken over by armed police earlier today. She was told there may be a bomb in the building opposite and later heard gun shots and the sound of gas.