Hackers who have hit the websites of the CIA, US Senate, Sony and others during a month-long rampage claimed on Monday to have knocked the site of Britain's Serious Organized Crime Agency (SOCA) offline.
"Tango down - soca.gov.uk - in the name of #AntiSec," the hacker group known as Lulz Security said in a message on their Twitter feed @lulzsec.
"Tango down" refers to the elimination of an enemy while "AntiSec" refers to "Operation Anti-Security," a campaign launched by Lulz Security against government websites.
Computer security firm Sophos said the SOCA website was sporadically inaccessible on Monday following the Lulz Security attack.
Sophos said it appeared to be a distributed denial of service attack in which a website is overwhelmed with traffic and becomes sluggish or unresponsive.
Lulz knocked the CIA's public website, cia.gov, out of commission for about two hours last week using a DDoS attack and also hacked into the US Senate's public website.
The group has also released tens of thousands of user names and passwords stolen from Sony and other sites.