There’s been an arrest

AFP

The investigation quite early led us to have concerns about the movement and activities of four men, three of whom came from the West Yorkshire area,” said the head of the Metropolitan Police anti-terrorist squad, Peter Clarke.

“We are trying to establish their movements in the run-up to last week’s attack and specifically to establish whether they all died in the explosions,” Clarke told reporters.

He added that it was “very likely” that one of the suspects was among those who died in one of the bombed Underground trains, near Aldgate station in east London.

Clarke said the “complex and intensive” investigation was “moving at great speed”, following raids on six premises in the industrial city of Leeds, in northern England, home to a large Muslim population of south Asian origin.

He said a man — identity and age not revealed — was arrested in West Yorkshire, the county that includes Leeds, and that he was being transferred to London for questioning.

Closer to the capital Tuesday, police sealed off a train station and parking lot in Luton, a town north of London, and carried out controlled explosions on a car with suspected links to the attacks.

London Update

Just following on from David, there is in fact a lot of blog activity. Tim Worstall is live blogging. John – shot from both sides – had to walk to work, Alex, the Yorskshire ranter can see things from his office window, Perfect.co.uk is also following things closely etc, etc.

As I said in comments, there seem to have been six bombs, five in tube stations and one on a bus. The Police are saying that incidents were reported at the Aldgate station near the Liverpool Street railway terminal, Edgware Road and King’s Cross in north London, Old Street in the financial district, Tavistock Square, and the bus in Russell Square in central London, near the British Museum.

Blair has said he is going down to London in the afternoon, but that the Gleneagles meeting will continue. The atmosphere will obviously be one of solidarity. This is aimed at the UK, but it is also a symbolic message to the entire G8.

There is no serious speculation yet about who this might be. This piece by Reuter’s security correspondant Mark Trevelyan is a reasonable rundown on the things which immediately appear to stand out.

Financial markets have, understandably, taken it badly, although I don’t imagine this will prove to be long lasting.

The UK authorities are understandably being very careful about handling information about casualties. They don’t want panic, and they don’t want useless speculation.

They also want to be able to inform as many next of kin as possible before releasing data, which I think is admirable.

The total number of dead, mercifully, may not be very large. There are though a considerable number of very seriously wounded.

Updated 13:00 UK time

Neil Mackintosh at the Guardian Blog reports that:

“A packed House of Commons is hearing a statement from Charles Clarke, the Home Secretary. He expresses sympathy to friends and family of those who had died, and says four explosions are confirmed. One on a tube train between Aldgate and Liverpool Street, one on a bus, one in the tube at King?s Cross. Tube.

The underground will remain closed for today at least. There are no buses operating in central London, with decision to reopen to be made later today. People are strongly advised not to travel into central London, with many mainline train companies cancelling services or terminating before the capital.”

Updated 13:30 UK Time
The number of actual explosions seems to have been confirmed at 4. This does not mean there were no more devices which did not go off.

Britain’s Home Secretary Charles Clarke said there were three explosions in the subway and one on a bus. “We do not know who or what organizations are responsible for these terrible criminal acts,” Clarke said.

A summary of the impact of the explosions can be found here.