Damned if you do and damned if you don't: Can NOT using AI amount to negligence?

Opinion, I have never been a legal practitioner in the UK:

As a generality, "NO". Why? Unless there is a specific professional standard for AI use, then "use AI" is either a quick-and-cheap checkbox, or a slippery slope to a bottomless pit of "you didn't use the right AI"..."you didn't ask it the right questions"..."you didn't cross-check it with other AI's"... crap.

(Yes, obviously AI's can be useful. And can also go disastrously wrong if you're incompetent or lazy.)