A British hacker who triggered a terrorist alert after hacking a US physics laboratory has received a light sentence of 200 hours community service.

19-year old Joseph  McElroy hacked the Fermi National Accelarator Laboratory in June last year, using the lab computers to store pirated music and software.

After the penetration was discovered, the system was shut down for three days and the US Department of Energy raised the alarm.

Scotland Yard's computer crimes unit traced the attack to the teenager, who could have faced five years in jail.

Judge Andrew Goymer said he had decided against a harsher sentence because McElroy had not accessed classified data, and had not intended to cause any damage.