Hacktivists Anonymous claim to have taken down Home Office website Hacktivists Anonymous claim to have taken down the Home Office website. It was not possible to access the site on Saturday evening. Photograph: Clara Molden/PA Hacking group Anonymous has claimed to have taken down the Home Office website with a cyber-attack announced days in advance. The website has been offline with a message reading: "Due to a high volume of traffic this page is currently unavailable." Anonymous announced on Twitter: "TANGO DOWN - http://www.homeoffice.gov.uk For your draconian surveillance proposals! Told you to #ExpectUs! The group was thought to have used a denial-of-service attack, where large numbers of computers overload a website with requests. If proven to be true, the incident could prove embarrassing for the government as the method is considered one of the least complicated tools in the hackers' arsenal. Anonymous had promised to carry out the mass assault in a tweet posted on Wednesday and a flurry of messages in following days encouraged supporters to join in. The message began "ruh roh!" and promised "an #Anonymous attack on the UK Home Office site" on Saturday. A flyer posted online said the action was taking place in support of three people facing extradition on hacking charges, including Gary McKinnon, who faces up to 60 years behind bars if he is deported to the US. Retired businessman Christopher Tappin, who has been extradited to the US on arms dealing charges, and Richard O'Dwyer, who is appealing against a similar fate over copyright infringement, also featured in the advert above the strapline "charge ya lazers." The flyer also gave the IP address for the Home Office's website. An article accompanying the online call to arms read: "A faction of hactivist group Anonymous in the UK has invited its supporters to draw digital arms in protest against the extradition of three UK citizens to the US." A message on a Twitter feed for a group calling itself AnonOpUK read: "#OpTrialAtHome a success, Well done everyone;) #Anonymous #AnonFamily." Before the attack started, the group tweeted: "Pre #OpTrialAtHome pizza is on way;)." The group also appeared to signal a countdown to the action an hour and 30 minutes before it started. The Home Office said in a statement: "We are aware of some reports that the Home Office website may be the subject of an online protest. We have put all potential measures in place and will be monitoring the situation very closely. If a successful denial of service attempt does occur tonight, we will liaise with the technical team and update as necessary. However the statement was still being released to news outlets after the site was taken down. A spokesman said: "We are aware of the situation and are working on it." A crackdown on Anonymous and similar groups, such as LulzSec has taken place on both sides of the Atlantic with a number of high-profile operations involving British police and the FBI.