There was probably nothing illegal (I'm very happy to be shown wrong).Tell it to the Judge
Dodgy Dave!
May aspects of British life assume reasonable moral behaviour (especially from people in authority), and it hasn't been found necessary to draft laws to make many specific immoral behaviours illegal. It isn't practicable to predict all potential immoral behaviours and legislate against them, and any attempt to make a 'generic' law would be so open to interpretation as to be useless.
The best that can be done is to draft relevant specific laws as it becomes clear they are needed; as has been suggested it this case by several politicians.