Boring, disappointing
I watched this because I like Robbie Coltrane, but I ended up feeling embarrassed for him and the rest of the cast. This is basically a 50-minute film ludicrously overloaded and padded into three episodes and a length of more than two hours (about 130 minutes). It's relentlessly confusing (flashbacks on flashbacks); it's frequently boring and tedious; it's full of red herrings (did Coltrane's character do the deed or didn't he?); there's little or no suspense or tension; the character of Carol is absurd and not credible; and, last but not least, the ending is downright terrible.
The Americans stopped making good mysteries a long time ago. I depend on the Brits to do it, and they really dropped the ball on this one. What an excuse for a 'mystery' this muddled, ponderous mess is.