A Twitter user has been found guilty of posting a "malicious" weblink which helped bring down the Home Office website.
Mark Johnson, 44, had denied posting links to his profile encouraging people to join a co-ordinated cyber attack on the page in 2012.
But a jury at Birmingham Crown Court found him guilty of encouraging or assisting the hacking effort.
Johnson, from Stoke-on-Trent, will be sentenced on 5 December.
He was also found guilty of encouraging web users to participate in a distributed denial of service (DDOS) attack on Home Secretary Theresa May's constituency homepage.
'Disaster recovery' website
During Johnson's trial the court heard both websites had been crippled after they were flooded with traffic over a two-day period.
The Home Office experienced 8,347 connections in a single half-hour period, according to prosecutors.
A back-up "disaster recovery" version of the website had to be activated after the main site was driven offline by the "co-ordinated" attack led by global hacking collective Anonymous, they said.
Johnson, of Josiah Wedgwood Street, admitted supporting the group's campaigns but maintained his social media accounts had been hacked when the links were posted.
West Midlands Senior Crown Prosecutor Warren Stanier said the attack, in June, caused "great inconvenience" to thousands of internet users.
"Mark Johnson's actions denied legitimate users the ability to use these two websites which contained important information for the general public," he said.