A primary school caretaker has been given an indeterminate jail sentence for carrying out a nationwide letter bomb campaign in which a Solihull business was targeted.
Miles Cooper, 27, from Cambridge, was told at Oxford Crown Court that he would have to serve at least five years.
He was found guilty by a jury on Thursday of 11 charges relating to explosive devices he sent to offices in Solihull, London, Berkshire, Oxfordshire, Kent and Swansea in January and February.
People who opened Cooper's padded envelopes were showered in glass fragments or nails, his four-day trial heard.
Cooper said he sent the seven letters, five of which exploded, in protest at Britain's "authoritarian" Government. He said he resorted to violent means as his peaceful protests against measures imposed by Tony Blair's administration had failed.
He told the court: "The overall goal was to shut down certain departments in certain buildings and ultimately to highlight my cause."
He denied eight counts of causing bodily injury by means of an explosive substance, two counts of using an explosive substance with intent to disable, one count of making explosives and one alternative count of possessing an explosive substance.
He did not deny sending the letters to three forensic science laboratories, a computer company, an accountancy firm, the DVLA and a residential address, but did deny intending to cause any injury.
Cooper said in evidence that his anger at the authorities intensified when his father, Clive, was unable to get DNA samples removed from the police database after he was cleared in 2003 of assault. "I felt my father had been used and I felt unable to do anything about it," he said.
It was then that he began making and sending bombs. Before this, Cooper had campaigned against the Labour Government's proposals to introduce ID cards. But after the episode with his father, his approach changed.
He said of the Government: "If you give a small group of people too much power, they will eventually end up abusing it.
"Based on what I learned at school and learned from history books, an authoritarian state eventually develops, and free speech is stifled."
Of Britain's "surveillance society", he said: "We are one of the most watched societies on the planet."
Cooper accepted the recipients of his letters were likely to suffer cuts and bruises when opening the packages but he said he intended no serious harm.
"The overall goal was to shut down certain departments in certain buildings and ultimately to highlight my cause," he said.
The devices caused widespread alarm. Michelle Evans, receptionist for Orchid Cellmark in Culham, was pregnant when she opened the first letter, which exploded, causing a small fragment to enter her thumb. The same day, LGC Forensics in Abingdon, Oxfordshire, and the Forensic Science Service in Solihull received similar devices.
All three made references to animal rights - designed to confuse police, according to Cooper.
A fourth device was addressed to Alpha Security at the home address of the company boss in Kent. A fifth was received at Capita's London office, from which the congestion charge is run, days later on February 5. A sixth arrived at Vantis, an administrator of speed cameras, on February 6, the court heard. The final device arrived at the DVLA in Swansea later that week.
It took the jury just an hour to find him guilty of all 11 charges against him.
The court heard that the attacks in January and February this year caused "a climate of fear" across the country and left the companies he targeted with bills of up to a million pounds.
Judge Julian Hall told Cooper he would have given him a determinate sentence of 10 years but ruled that he was a danger to the public and handed him an indeterminate sentence. Cooper must serve a minimum of five years minus the 116 days he has already spent in custody.
He said: "First and foremost you are a terrorist, let there be no mistake. Anyone who tries through violence or threat of violence to change the political will is a terrorist and that is precisely what you did."
When police swooped on Cooper's home in Cherry Hinton, near Cambridge, they discovered "a bomb factory" in his bedroom with three more devices ready to send.
Judge Hall yesterday heard the frightening amount of explosive material and other experimental items that Cooper had hoarded in his bedroom.
Gareth Branston, prosecuting, told the court that officers found a variety of household items which had been adapted to make explosives and also chemicals that experts said had been used by Islamic terrorists.
He said investigators discovered 31 fireworks, four packets of sparklers, 23 packs of party poppers and six packs of incense sticks.
They also found wires, pipe bombs, drain cleaner, weed killer and moth balls which could all be used to create an explosive effect. Among the weapons which were also discovered were a small home-made crossbow, a home-made rifle, a machete and two air rifles.
Mr Branston said the chemicals TATP and HMTD were also found. Bomb disposal agencies say they are used by terrorists and are ignited by a small bulb, such as a Christmas tree bulb, of which a number were found in Cooper's possession.
He also had a number of books with titles including The Shooters Handbook, High Explosives And Repellents, and Home-made Guns And Home-made Ammo.
Mr Branston said: "The Crown suggests that the defendant's motivation was as much to do with his interest in explosives as much as anything else.
"Contrary to his assertion he was downgrading his devices, he was capable of upping the ante considerably. He was going to build further and despatch more dangerous devices."
Authorities also examined his computer and found he had searched on the web for "letter bomb" and also found evidence that he had been investigating how to make explosive devices.
One site he visited featured a lengthy report from the US Congress entitled Who Becomes A Terrorist And Why?
He had also been swapping tips with other web users about weapons on an internet forum.
Judge Hall said Cooper had caused lasting psychological damage to his victims and caused massive disruption to the organisations which he targeted. He said Cooper was a coward who tried to avoid detection.
He told him: "Either what you did was rational, in which case it was evil, or it was irrational which, in my mind, makes it even more frightening.
"You didn't follow up your campaign of terror with any attempts at publicity trying to make your point.
"It makes one doubt your motives. I think you had a double motive and simply didn't care if people were hurt.
"You come across as a quite unemotional young man with little empathy for others.
"Your first device was described as 'genius'. There is nothing in the evidence to suggest in any way that you intended to stop your campaign if you had not been arrested.
"It is all too sad that one can from the internet download recipes for making high explosives and you have done just that.
"Your material at your home was capable of being designed into all types of explosives.
"Why should I believe your experiments had ceased? Why would you ever have stopped your campaign?
"I have no hesitation in finding you a serious risk of harm to the public.
"If ever the public should be protected from someone it is you."
Michael Wolkind QC, defending Cooper, said he was "lost and obsessed by his misguided campaign".
He added: "He wasn't planning to escalate the campaign, he was trying to devise a series of items that would cause less harm."
Mr Wolkind said Cooper had told a psychiatrist: "An urban guerrilla is useless when discovered."