Peter Mullan gave a stunning performance in a series which just dragged on too long. The flashbacks would have been better as a prologue at the beginning as they became boring to the point of being really annoying. I know that the intent was to show Richie losing his mind, but the four part series could have been reduced to two hours with no loss.
Two things puzzled me: why did no one turn the illegal immigrant gangsters into the police/immigration service, then they would have been rid of them? and the progression of Ritchie's Alzheimer's Disease must have been the fastest on record. My observation of dementia and Alzheimer's has been that it takes years rather than days.
Overall, 'The Long Good Friday' did it better.