Letter bombing suspect held as police swoop in dawn raid

The suspect, named by sources as Miles Cooper, who is in his 20s, was arrested this morning in a Cambridgeshire village, after officers probed a link with a parcel bomb sent to a local Labour Party office last August.

And police chiefs warned they could not rule out the possibility that more devices were already in the post.

A house in the village of Cherry Hinton was cordoned off as forensic teams began a search of the property, which police expect to last for "several days".

Anton Setchell, the Association of Chief Police officers' national coordinator for domestic extremism, said: "At this stage I am not able to guarantee that there is not another postal package containing an explosive device within the postal system."

The first three letter bombs last month were sent to forensic science laboratories in the West Midlands and Oxfordshire.

They were followed by an attack on a house in Folkestone, Kent and three letter bombs on consecutive days at motoring-related companies in London, Berkshire and Swansea.

The Driver and Vehicle Licensing Agency and the offices of the company which runs London's congestion charging system were among the targets.

At least one of the packages is said to have featured a Cambridgeshire post mark. Detectives believe all seven letter bombs are linked.

In each of the recent attacks, the bombs have been home-made pyrotechnic-style devices in A5 jiffy bags. At least two contained glass.

Forces close to the investigation described this morning's arrest as a "very significant" development.

The suspect is being held at an undisclosed police station and was to be questioned by detectives later today.

It is understood the investigation has focussed on animal rights extremists as well as the possibility that a disgruntled motorist or someone aggrieved by Britain's increasing surveillance society could be behind the bombings.

There is no immediate indication today as to whether the arrested man has any connections to one or other of these theories.

Police have also refused to say whether they have intercepted any other letter bombs since the investigation began.

Mr Setchell said: "The previous seven devices have all been contained in A5 size jiffy-type padded envelopes.

"I am therefore renewing my request for the public to maintain their vigilance and not to handle any post which appears in any way suspicious.

"If anyone is concerned about any package that arrives in the post they should contact their local police immediately," added Mr Setchell.

A woman was injured when a letter bomb ignited at a DNA testing firm in Oxfordshire - the only injury caused by the first three explosions.

Security director Mike Wingfield, 53, then suffered minor injuries when he opened a letter bomb at his home in Folkestone, which he also uses as a business address.

A woman was hurt in the explosion at the Capita office building in central London and two men were injured at an explosion on an industrial estate in Wokingham, Berkshire.

In the most serious of the seven letter bombs, four people were injured when a letter bomb went off in the post room of the DVLA in Swansea.