I watched Red Election series. It was a little far fetched even though it seemed to be set in a present day era, the details and scenery were as real as I suppose they could manage. Downing street and number 10 had the famous staircase but the wrong way round. The plot is a secret mission by the Russians to manipulate a Scottish independance vote, and manipulated the result so Scotland became independant, and then invade Scotland with the pretence of helping repair a nuclear reactor disaster, which they also caused. The operation was called Redback.
Mi5 offices looked more like it was set in an old school building, and consisted of about five or six agents. The head of which made drastic errors in judgement due to being worried a black man needs to be better, because of the racist upbringing he suffered.
It promised to be a great spy/who dunnit type of series, but failed with its lack of believability in many areas. The ending was confusing, and I expected a episode 11 to be the final one, not episode 10 that left me feeling it was not the end, as many things were not resolved.