People ask Bryan Cranston where the "rise" of sinister alter-ego Heisenberg comes from. He says from the first episode, when he tried to be someone else. Yet the dark truths of his journey downhill reveal so much more.
All the characters are in thrall to their institutions, whether they be the English legal system in the case of Heaslop, of English-led colleges for Fielding, or the larger institution of the British Raj itself.
If there's a subtext to New Tricks, it's that modern policing is too cautious, too sterile to handle the rough and tumble of proper police work. To really nail the bad guys, coppers need to be free to be themselves, unencumbered by the constraints of political correctness.