The chairman of SOCA, Sir Ian Andrews, has submitted the following letter of resignation to the chairman of the Home Affairs Select Committee:
The chairman of Soca has resigned according to statement on the agency's website.
Guardian crime correspondent Sandra Laville has tweeted that the chief of the Serious Organised Crime Agency (Soca) has resigned.
Soca have confirmed that their website continues to be offline following a hacking attempt.
A spokesman stressed that the attack did not pose any operational threat.
A Soca spokesman said the distributed denial of service attack (DDOS), which involves web addresses being hit by a flood of visits, did "not pose any security risk to the organisation".
Previous DDOS attacks have been linked to the loose-knit international "hacktivist" group Anonymous.