Five men have been arrested over a spate of recent web attacks carried out in support of Wikileaks.
The five males are being held after a series of arrests at residential addresses in the West Midlands, Northamptonshire, Hertfordshire, Surrey and London this morning.
The men were arrested in relation to recent and ongoing attacks by an online group that calls itself "Anonymous".
Targets included the websites of PayPal, Mastercard and Amazon.
Anonymous used a technique called "distributed denial of service" (DDoS) attacks in a bid to take the sites offline.
DDoS attacks bombard a website with data until they cannot respond, rendering them inaccessible.
Not all the group's attempts succeeded.
In December, they abandoned an attack on the online retailer Amazon after it could not muster enough people to take part.
The group used an online tool called LOIC to allow members to easily take part in the bombardments of websites.
The site from which it could be downloaded reassured people that there was "next to zero" chance that anyone who used it would be caught.
But a study found that the tool makes no attempt to hide a user's net address which would lead any investigator almost straight to an attacker.
Thousands of people are thought to have downloaded versions of the tool.
The Anonymous group maintained that they were not hackers but "average internet citizens" who felt motivated to act because of perceived injustices against the whistle-blowing website Wikileaks.
Many of the targets had withdrawn services from Wikileaks before they were attacked.
In recent weeks the group has turned its attention to targets in Tunisia and Egypt, attacking official sites in both countries in support of anti-government protests.
The five were arrested this morning at 0700 GMT in connection with offences under the Computer Misuse Act.
Three teenagers aged 15, 16 and 19, were arrested with two men, aged 20 and 26 in coordinated arrests.
This investigation by the Central e-Crime Unit was carried out in conjunction with law enforcement agencies in Europe and the US.
All five have been taken to local police stations where they remain in custody.
It is not the first arrests in relation to the attacks. In December two Dutch teenagers were taken into custody and subsequently released over allegations that they had helped coordinate them.