"He's a bloody genius."
James says it to annoy the Chief Super, but also because he needs to say it, and who else can he tell?
Not the other detectives. If he praises Lewis, 'sodding arse-licker' is the mildest name they'll call him.
Not Hobson, who is overly perceptive about the living as well as the dead.
Never Lewis himself. Part of James's job is to challenge his governor, keep him from complacency. Besides, if he admits to admiring the cop, he might reveal his feelings about the man. Then he would be lost.
James suspects he is already lost.