Hackers affiliated with the Teampoison Black-Hat group have attacked MI6 in protest at what is said was the detention of innocent people on terrorism charges.
The group, which recently defaced Croatia's Nato website in protest at Western military intervention in Libya in 2011, launched a "phone bomb" on MI6's London office, making non-stop calls for 24 hours.
"Every time they picked up the phone the server would play a robot voice which said 'Teampoison'," the leader of the group, called Trick, told Softpedia website.
The attack amounts to a phone denial of service akin to the Anonymous collective's most common hacking tool, the Distributed Denial of Service (DDoS).
In the phone bomb, the hacker can be heard goading MI6 officials who threatened to alert the FBI.
"My name is Trick, I'm from Teampoison, my name is Robert West," says the voice. "I got some terrorism for you here."
The officers ask him where he is. "I'm in the UK," Trick replies. "I don't brush my teeth, I like tea, I'm from the UK."
"What's your actual philosophy?" asked the official. "I'm not familiar with it."
"Our philosophy is pretty simple, it's knowledge is power," said the hacker. "And, uh, f**k the po-lice."
"Yeah..." replies the official.
Teampoison also released a leaked call from the office in which agents discuss the attack along with the Teampoison statement condemning counter-terrorism strategies.
According to Teampoison, MI6 was targeted because officials "help lock up innocent people they themselves label as terrorists with no proof at all".
The reason given for the latest attack was the extradition of Babar Ahmad, Adel Abdel Bary and others from the UK for trial in the US.
"We all know how the US treats innocent Muslims they label as terrorists, eg - Aafia Siddiqui," said Teampoison.
Babar Ahmad and four other terror suspects lost their battle at the European Court of Human Rights against extradition.
Ahmad was first arrested in December 2003 and then released without charge. In August 2004, he was arrested again and and accused of running an important pro-jihad site, Azzam. The website allegedly played a role in inciting hatred against the West among young Muslims in Europe.
Bary has been held in the UK without trial for one of the longest periods on record. He has been accused of being Osama Bin Laden's right-hand man in London and of promoting violent jihad against the West.
"Adel Abdel Bary has been in prison for 12 years in the UK. Apparently he received a phone call from Osama years ago, therefore they imprisoned him claiming they had a tape of the call but there was never a witness to prove it or show the tape," reads Trick's statement. "If I was to call George Bush would they lock George Bush up for receiving a phone call from a cyber-terrorist/hacker?"
Teampoison is affiliated with many anti-US and anti-Israel hacking teams such as Mujahideen Hacking Unit and ZCompany Hacking Crew (ZHC).
It is a rival of LulzSec, an offshoot of the Anonymous group which declared it was disbanding nine months ago after almost 50 days of constant attacks.
In February, six of the group's most prominent members were arrested after the most prominent of them, known as Sabu, turned informant.
Teampoison released in June 2011 the alleged personal details of various LulzSec members alongside information on the AnonOps IRC server, including IP addresses and passwords.
For further news on Teampoison's recent activities, check out the IBTimes UK Cyber Warfare section.