Armed police have surrounded two properties in a block of flats in west London in a major operation.
Eye witnesses say they heard three shots and a large explosion as officers wearing gas marks entered the property.
The area, around Basing Street, near Notting Hill, has been cordoned off and the area has been evacuated.
Have you witnessed the current events in West London? Do you have any pictures of the latest developments?
You can send any footage or pictures you may have to 07921 648 159 or to firstname.lastname@example.org
This debate is now closed. Read a selection of your comments below.
The following comments reflect the balance of opinion received so far:
I feel that the poor Brazilian man and the police officer who shot him are both the victims of these evil terrorists who are intent on causing death and destruction. Not only has a family lost a loved one, but I am sure it will have completely ruined the officer and family's life as well - he now has to live with what happened. The blame lies solely on the bombers whose actions have caused the need for a shoot to kill policy.
Sally, London, UK
I commend the police force in apprehending the bomb suspect without injury. But worry the tube shooting may politically handcuff the judgement of officers.
Chris Green, Duncan, Canada
The police need to use all means necessary to extract information out of the caught bomber in order to catch his accomplices.
Abu Labeebah, London
I'm so pleased that police have caught one of these men alive. One of the frustrations of suicide bombing is that the perpetrators never have to face up to their disgusting crime, and this man most certainly will. I suspect that life in a UK prison won't be quite the 'paradise' he had in mind, and I for one am unashamedly gleeful.
How is it so difficult to find these people? Are they being sheltered? It's time for all UK citizens to step forward and help
I live one road up from the bus bomber's mum and dad's house - I found out yesterday when reporters turned up. It just goes to show we don't know what is on our own doorsteps.
I don't understand the police. They shot an innocent person eight times and when it comes to the actual bomber they use a stun gun.
David, East London
I feel very proud of the way our security services are handling this and of the way that as a democratic nation, the truth behind the erroneous killing of the innocent Brazilian was so widely reported last week.
It will be interesting to see if they can get any information out of the suspect. Since he was willing to die for his cause, I am not sure how effective standard interrogation will be.
Sam, Alton, Hants
Perhaps we should all be a bit more observant and pay closer attention to what goes on in our neighbourhoods. Nosy neighbours peeping from behind net curtains may rightly be an object of derision but nevertheless a healthy interest in what neighbours are doing might act as a deterrent.
M. Wilson, UK
Despite the tragic shooting of the Brazilian last week, I still have to praise the police for the work they are doing in light of the extreme threat now facing this country. I was not in favour of the war in Iraq but innocent people cannot be blamed for politicians' decisions so I think people who want to kill innocents should face the harshest punishment.
Jayne Barratt, Birmingham
Although it was unfortunate that an innocent man was shot dead by police last week, it is important that the police remain vigilant and not allow incidents like this to shatter confidence.
I think the police may be jumping to conclusions and arresting anyone who fits a certain profile. They should be careful not to stir up cultural tensions and look to build relations with the community. This will be more effective in helping them conclude their investigation.
Khaled Arikat, London, UK
Someone asked why wasn't a Taser gun used last Friday? As an electronics engineer, I would say it would definitely set off a bomb. A Taser gun stuns by creating a large electric charge which could then trigger any detonating device. Sorry, a nice try but it's a non-starter.
Mark, Hemel Hempstead, UK
I am very proud of our police force. It makes me feel we are in good hands. What I am more worried about is the safety of our police force. They are in the frontline and possibly would be a close range of a suicide bomber. Are there ways to protect the police who are in the frontline?
Christina Spybey, London, UK
To Mr. Khan, while I appreciate your concern, it worries me that this only seems an issue when it's on your front doorstep. This is countrywide and with the threat to the innocent public - we all have to come together and defend our collective front doorstep. I am impressed by the speed of the police investigation and while very concerned about their actions when involved with Friday's shooting - I commend them on a brave and thorough job.
Rachael , London
In the current environment the police clearly need the ability to disable a suspect swiftly and temporarily with the prime aim of controlling the situation. It is equally important that the risk of undesirable side effects is minimised. I have every confidence that those responsible for procuring the taser gun and authorising its use have taken all this into account. However, given that the police have weapons like the taser at their disposal, when is a 'shoot to kill' policy ever justified?
Martin Herring, Bristol
I do hope the police have chosen to use the Tazer gun rather than a conventional firearm. I just hope the aren't pandering to the 'shoot him in the hand' brigade - these are dangerous times and thus require drastic measures. We cannot allow ourselves to be dictated to by liberalists and advocates of 'liberty' who attempt to undermine our security in the guise of political correctness.
Alan Taylor, Liverpool UK
I would give the police my full support in anything they have to do to stop these bombers, including a "shoot to kill" policy", providing that the public have been warned that we are in a maximum alert situation and a shoot to kill policy is in operation and anyone who does not stop or co-operate with the police will be shot. However, where possible, stun guns should be used.
Mrs Sylvia Lay-Flurrie,
The police and security services are doing an excellent work in very dangerous environment, we are in now. Unfortunately we are too quick to condemn them, when some thing goes wrong.
Mohammed Jamil, Birmingham, UK
I feel protected and reassured by the swift and decisive actions of the security forces. I am quite sure any impressionable youngsters who might have harboured notions about this being a cause worth taking up will now have a rethink.
I worked for the security services in Iraq, and there is absolutely no way of telling if someone is a bomber or not. The police made the right decision, however unfortunate, but they now have to live with that memory.
Darrell Jones, Warwick
Despite the fact that I think the police need to be very careful about the application of their shoot-to-kill policy, I've been very impressed by the speed and professionalism of the investigation itself. The use of a Taser here is also encouraging, although that may not have been practical in last Friday's incident.
Colin Wright, UK
The rapidity with which men have been arrested and the way the pieces have been put together speaks volumes for police intelligence. This will reassure the public and will also send a very strong signal to the terrorists that their path of violence is doomed to failure.
Pancha Chandra, Brussels, Belgium
Although the police have found a few people, I am still terrified. Everyone else is too and it will be a long time and take many more breakthroughs before we all feel safe again.
Neil Lithgo, Walthamstow, London
I couldn't believe it - I could see the 9th floor of Curtis House clear as day from the kitchen window of my old flat. You never know who your neighbours are these days.
It looks like the police have had a success after the dreadful incident last week. Welcome news! The authorities are overall doing a very impressive job and deserve the support of the public. The use of a taser weapon seems to point to lesson learned from the tragic death of an innocent man.
I hope the police aren't using taser guns instead of conventional firearms because of the tragic mistake made in killing the Brazilian man last week. The Government and the police must not downgrade their shoot-to-kill policy. The police deserve to ensure their own safety as they go about making the world securer for us.
The speed of the police investigation is very impressive. These people are obviously the tools of a bigger machine. Getting to the roots of the organisations that train, fund and recruit is going to be a much harder, longer more dangerous task.
Ian Paterson, Shepherds Bush
I would like to commend the police for the work they have done so far, working in what are extremely difficult circumstances. Those criticising the police should perhaps be reminded that they are working for the safety of everyone. Mistakes, such as the tragic shooting of the Brazilian gentleman are, unfortunately, a part of the price we must pay in the current climate.
Gillian, ex-pat, Germany
What is concerning me most is that following the arrests made in Leeds and now Birmingham, the location of these extremists seem to be countrywide. The police should be given as much power as necessary in all areas of the country to tackle the issues.
To John, Wembley: Tazers are great but you do have to get within about 12 feet of a suspect to use one. That's much closer than I'd like to get to a suspected suicide bomber. We don't realise how brave our police are.
The reason a tazer was not used last Friday is because it doesn't immediately incapacitate. It electrocutes, as its name would suggest, therefore allowing said suicide bomber to detonate his explosives. I think the police and security services have done a fantastic job since the first bombings; they have reassured the public at every opportunity and have seemingly identified the bombers exceptionally quickly.
I have nothing but the utmost pride in the way the police are moving on with the whole terrorist situation. One question I have is if a Tazer gun is used on a primed suicide bomber wouldn't that cause an explosion?
Despite last week's sad news, I think the security services are doing a first class job in dealing with this threat as swiftly as possible. I have a lot of respect for the police given the unenviable task that they are facing.
Andy Bird, Cheshire, UK
I believe the police and other agencies involved have done an excellent job thus far to prevent the inevitable attacks. However a firm stance with the current suspect, if properly identified would be essential.
Alexander Taylor, Liverpool
I'm really concerned about what has happened today in Birmingham. I live around the corner from the evacuation and it really concerns me that we are facing this on our own doorstep.
Mr Khan, Small Heath, Birmingham
I am glad this time the police appear to have made arrests without shooting anyone. This will help rebuild some confidence in them after the shooting of an innocent man last week.
Paul, London, UK
The taser gun is a good idea but only if it will stop innocent people being killed by the police. Why was this method not used last Friday?
John Agyeman, Wembley