A man who sent a deadly letter bomb to staff at a Hoxton Bitcoin company because they refused to change his password has been jailed for six-and-a-half years.

Jermu Michael Salonen, 43, of Gullspång, Sweden, sent the device in a padded envelope to two workers at Cryptopay, though it was delivered to another office.

An employee began opening it not realising it contained a bomb but thanfkully stopped when he became suspicious. Police were instead called and the device was made safe.

Forensic specialists recovered DNA and after it failed to find a UK match Interpol were called and Salonen was identified as he was known to Swedish authorities.

He was arrested in May over the bomb and other letters to high-profile figures in Sweden and London.

The only possible motive police could establish was that Salonen, a customer of Cryptopay, had emailed them in August last year asking them to change his password, which they said they couldn’t do.

Today, a judge in Sweden found Salonen guilty of attempted murder. He was also convicted for sending the letters, for which he was sentenced to a further six months’ imprisonment.

Cdr Clarke Jarrett, head of the Met’s counter terror unit, said: “Salonen seemingly made and sent a device that had the capability to seriously harm and even kill over something as inconsequential as a change of password.

“Fortunately the bomb did not detonate. It was due to sheer luck that the recipient ripped opened the package in the middle rather than using the envelope flap which would have activated the device.”