According to NSA documents leaked by Edward Snowden, a special unit of the British intelligence agency GCHQ had begun carrying out DOS attacks on IRC servers used by hacktivists, mainly Anonymous and LulzSec.
The unit responsible for these attacks (JTRIG) not only used DOS attacks, but also other techniques. 80% of the people who frequented Anonymous' IRC channels were said to be intimidated by the attacks, resulting in them being kicked out of the IRC rooms.
In June 2012, the administrators of the IRC Network VoxAnon informed users that a "heavy DDOS attack" had led to a temporary disruption of their activities.
It is possible that this attack was carried out by agents of the British intelligence.
The GCHQ special unit is also responsible for identifying the hacktivists who attacked PayPal and government websites, according to the documents. Many Anonymous and LulzSec hackers had no idea they were actually talking to secret agents.
For example, Edward Pearson, known online as GZero, was arrested in 2012 as part of a JTRIG operation and sentenced to 2.5 years in prison. The same spy unit is also said to have been instrumental in the arrest and conviction of Jake Davis, also known as Topiary, and Mustafa al-Bassam, also known as Tflow.
