Security Service (MI5)
MI5 headquarters at Thames House, London (Txllxt TxllxT, CC4.0).
.jpg){kind=link}
The Security Service, colloquially known as MI5, is the main British domestic intelligence service.
Keep reading with a 7-day free trial
Subscribe to Tom Griffin on intelligence history to keep reading this post and get 7 days of free access to the full post archives.