The distribution denial of service (DDoS) attacked the soca.gov.uk late Wednesday, SOCA confirmed to BBC.

"We took action to limit the impact on other clients hosted by the (same) service provider," the spokesman said.

A DDoS attack is a common technique in which sites are overloaded with date requests, causing them to fall over. It would cause temporary inconvenience to website visitors but do not pose a security risk.

"SOCA's website contains only publicly available information and does not provide access to operational materials," the spokesman added.

The spokesman said that no confidential information had been lost during the incident, but declined to say whether they had traced the source or motive of the attack.

The agency, which investigates serious crimes like people smuggling, drug trafficking and shootings, last month shut down 36 web domains being used to sell stolen credit card data.