There seems to be quite a lot of discontent behind the scenes on New Tricks. Widely reported & this is the account I first read: www.bbc.co.uk/news/entertainment-arts-19331320
I tend to agree it has become a tad mundane in terms of characterisation, but that seems to happen in most long-running series. Perhaps it is time to pull the plug.
A little interesting fact: James Bolam's wife, Susan Jameson, plays Brian's wife in the series 
It's official: Grandparents are good for children




