Miles Cooper has been found guilty at Oxford Crown Court

Miles Cooper, 27, from Cambridge, told Oxford Crown Court he had been angry at authorities and "concerned about the direction my country was heading in".

Seven letter bombs were sent to addresses in England and Wales earlier this year, five of which exploded.

Cooper, who was convicted on 11 counts, will be sentenced on Friday.

Cooper had told the court his aim was "ultimately to highlight my cause" and denied charges related to the seven letter bombs sent in January and February.

He did not contest that he sent the letters to three forensic science laboratories, a computer company, an accountancy firm, the DVLA and a residential address, but denied intending to cause injury.

The locations were Abingdon in Oxfordshire; Culham, near Abingdon; Birmingham; Folkestone, in Kent; Victoria in central London; Wokingham in Berkshire; and the DVLA offices in Swansea.

'Fear not harm'

Mr Cooper had told the jury his anger at the country's authorities had intensified when his father Clive was unable to have DNA samples removed from the police database, even though he had been cleared in 2003 of assault.

I am genuinely ashamed of what I've done Miles Cooper Where devices were sent Bomber terrorised nation

"I felt my father had been used and I felt unable to do anything about it," he said.

Cooper had also earlier told the court the letters he sent containing explosive devices were intended to cause fear rather than harm.

They were sent, he added, to organisations he believed were connected to government control, surveillance and monitoring.

"I was hoping to achieve a bomb scare, to shut down a building, but cause no real harm to any individual," he said.

"The overall goal was to shut down certain departments in certain buildings and ultimately to highlight my cause.

"I am genuinely ashamed of what I've done."

During his testimony, Cooper said he had concerns over the amount of power given to the government.

"If you give a small group of people [the government] too much power, they will eventually end up abusing it."

Referring to the issue of Britain being a "surveillance society", he said: "We are one of the most watched societies on the planet."