In a city the size of London, could both be true? It seems to me with all the trouble they've had with so-called imams over the past few years that there are bound to be active cells -- and those cells might have placed the suicide bombers. From what I've heard, though -- and this is purely guesswork at this point -- some people are leaning towards bomb packages.
I agree it's unclear just yet. The deal with IRA ASUs (active service units) was that they'd have to sneak into the UK, because all the players that could lead such a cell were known. They'd then go to ground at a safe house, use young unknown players for the legwork and then they'd try to pull off a string of terrorist incidents over a fairly short time, until they either went home, got caught or got SAS'd.
If the perpetrators here are from Iraq or some other foreign country, then it'd probably work in much the same way.
If they're locals though, it might not and they might try to keep a low profile for a while.
My guess though is that the UK security services will have a very good idea about any locals that would do such things and will catch them swiftly. This is precisely the point of allowing them to run around loose and say what they like.
Friend just sent me this; have no idea where he got it, but it seems urgent:
Fire fight between troops in Britain and terrorists at Woburn Place.
The British have given chase to some people near Woburn Place.
There are troops in Woburn Place. When I left my home in Bloomsbury, I saw helicopters landing in Coram's Fields. They say the troops are looking for someone. Now troops are arriving by the busloads near Guildford Street. I heard gunfire in Woburn Place.
From a commenter at La Repubblica