Shortly after I received a reply, also on Twitter, from what pertained to be the MI5 Twitter account, pointing out that the service website contains a history of the Security Service. Looking at their feed, it was obvious they were spending a reasonable amount of time following the hashtag #MI5, and then replying to things that had been said. I found this slightly odd, as more usually the overt use of Twitter by insitutions is to disseminate their press releases and statements, rather than get dragged into debate with Tom, Dick and Harry.
Over the weekend I emailed MI5, via the contact form on their website. Was the twitter account theirs? On Monday 18 July I received the following reply:
Thank you for your enquiry.
This is not an authorised Security Service account.
The Enquiries Team
The Security Service
So - who is posing as MI5 on twitter? Looking now, the account I refer to appears to have been closed, and with it all records of the tweets it sent out. Does anyone have any further information on this rather curious affair?