Hackers associated with Anonymous brought down the websites of the prime minister, the Ministry of Justice and the Home Office over the weekend.
In a distributed denial-of-service campaign dubbed Operation Trial At Home, Anonymous claimed to be engaging in a 'digital protest' at the looming extraditions of Gary McKinnon, Christopher Tappin and Richard O'Dwyer to the US. The cases of the three men are central to growing unease over the UK-US extradition agreement.
"Anonymous launched a cyberattack on number10.gov.uk, homeoffice.gov.uk and justice.gov.uk resulting in multiple tango downs," a frequently used Anonymous Twitter account stated on Saturday.
Under the two countries' extradition agreement, put in place in the early days of the 'war on terror', a UK citizen can be extradited to the US without the US authorities having to show UK courts any evidence to support their charges against that person. The arrangement does not work the other way round.
According to Downing Street, David Cameron recently spoke with Barack Obama about revising the extradition deal.
The case of Gary McKinnon has been the most visible focal point for discussions over the treaty. The self-confessed NASA hacker has been fighting extradition since 2004 — he admits having hacked into NASA's systems in 2001-2, but concerns over his Asperger's Syndrome have so far kept him from being extradited.
Last month home secretary Theresa May signed extradition papers for Richard O'Dwyer, a British computer science student who the US authorities want to try for running an allegedly copyright-infringing site called TVshack.net.
Meanwhile, Tappin has already been extradited, and is currently in a New Mexico jail. He is awaiting trial for illegally exporting weapons parts to Iran, but has himself accused US authorities of entrapment.
Despite many arrests over its attacks, the Anonymous collective continues to maintain a high level of activity, related to a number of causes.
Last week the group said it had hacked hundreds of Chinese websites in protest over human rights abuses. It reportedly also disrupted the websites of two US trade organisations, USTelecom and TechAmerica, over their support for a new cybersecurity bill.