British Attack Anonymous... Using Anonymous' Tactics?

Yet another scandal has had the lid blown off by Edward Snowden with the revelation that the GCHQ used a DDoS attack on the hacktivist group Anonymous and LulzSec, originally reported on by NBC news. This time, the attack against Anonymous used the same tactics used by some Anonymous activist, that have since sent them to jail. But as a GCHQ spokesperson claimed, "all of GCHQ's work is carried out in accordance with a strict legal and policy framework." 

So, when Anonymous performs a DDoS, it's illegal. When GCHQ does it, it's completely legal.