With the case headed to trial, Leonard is facing the prospect of public denunciation. Instead of confronting the problem, he embraces decadence, listening to jazz, drinking, and smoking. Leonard learns that he will be removed from his post as the curate regardless of the trial’s outcome. He receives a six-month prison sentence for gross indecency — which throws off-course his and Daniel’s plans to move to someplace new.

Source: https://www.distractify.com/p/what-happens-to-leonard-in-grantchester