Given the political nature of the detention, I suspect that the action would be known about at cabinet level. It is difficult to work out if this was primarily

Given the political nature of the detention, I suspect that the action would be known about at cabinet level. It is difficult to work out if this was primarily driven by the Home Office, the Foreign Office, or the Department of Transport, given that they all have a role in border security - but the action was almost certainly proposed by a civil servant at one of these institutions - possibly acting on a request from the security services. Given that David Miranda was transiting through the country, I would guess that the request originated from MI6, which would mean that the request was routed through the FCO, which would put William Hague in the hot-seat. Helpfully, the Guardian has a list of senior civil servants here (although it is quite out of date): http://www.theguardian.com/news/datablog/2011/jun/16/civil-service-organisation-charts http://www.theguardian.com/news/datablog/2011/jun/16/civil-s... We could probably make some guesses as to which roles were involved in the decision. (Note: Civil servants only stay in a role for a limited period of time, so it is probable that the individuals named in the above list have moved on to new roles by now, and are not involved).