New London Explosions

There have been four small explosions in London - three on the tube and one on a bus - two weeks to the day after the bombings which took 55 lives.

So far details are unclear but AP are saying the explosions were by detonators only. They don't say whether there were bombs attached to the detonators which failed to explode or whether the detonators were all there was. Eyewitnesses report hearing a sound like a popping champagne cork and then acrid smoke.

Given the size of the explosions the emergency services were quite right to err on the side of caution by sending in rescue workers in full protective suits. Such small bombs could have been a dispersal method for chemical agents but thankfully that has not been the case.

Only one person is being reported injured and no reports of deaths have been made.

There are also reports of armed police entering University College Hospital, near Warren Street tube station hit by one of the small blasts, searching for a black or possibly asian man with wires protruding from his clothes. One has to assume this is connected to the earlier detonations.

The big question right now is whether these are copycat explosions or a follow-on attack by another terrorist cell linked to the original explosions.

I am inclined towards the former, to be honest. The timing - later in the day rather than during rush hour - and the small scale of the explosions suggest a sole idiot or a bunch of idiots copying the original attack for their own agenda. The explosions were not closely timed. In two cases (at the Oval and Shepherd's Bush) eyewitnesses report a person running off the train just after the explosion.

The BBC has more news as it develops.

Update 10.45 am Central

This from Richard Norton-Taylor, Guardian security editor, on the Guardian's Newsblog:

One thing is clear about this afternoon's events: the bombers and bomb makers were very different from the suicide bombers whose attacks exactly two weeks ago killed more than 50 people.

First indications suggested those responsible for today’s attacks were "amateurs" and their bombs were crude. There is a report for example, that one of the devices was a nail bomb.

This time, the police have more evidence to help them in their investigations. The devices themselves, for a start. There are reports as I write that the police have captured the bomber at Warren Street, or chased him into a nearby hospital. There also should be valuable evidence from CCTV cameras.

Update 11.10am Central

The BBC says that two people have been arrested in connection with today's explosions. They also say that there are definitely no traces of chemicals at any of the locations and that the incident at University College Hospital has been "stood down".

Update 1.45pm Central

AP has opinion from two respected British experts on terrorism:

Jeremy Binnie, an analyst with the London-based Jane's Terrorism and Insurgency Center, said there were key differences between Thursday's explosions and the previous blasts.

The latest ones did not take place at rush hour, they targeted more outlying stations, and "if there were bombs, they seem to have been duds," Binnie said.

"It seems much more amateurish in many ways," he told The Associated Press.

That could suggest they were a copycat operation, but Binnie cautioned that it was too early to tell. He noted that investigations into the July 7 blasts showed signs there could be a second cell in existence.

Keith Burnet, an expert at the Royal Institute for International Affairs in London, also said the blasts appeared to be part of a "copycat exercise, carried out by people not as sophisticated as the bombers who struck on July 7."