Anyone else notice this snippet on the BBC news coverage of the whole saga:
"The UK authorities became aware of the exchange only in June 2013, a month after Fusilier Rigby was murdered."
"After the murder of Fusilier Rigby an unidentified third party provided a transcript of the conversation to GCHQ."
So, who provided them with the message from Facebook? Sounds to me like GCHQ/NSA had access to this message all along....