© Copyright 2003-2019 Heliflight UK Ltd
If you want to fly in the hours of darkness you will need to add a night qualification to your licence. This involves 10 hours of instrument flying and 5 hours of flying at night. You will practice night navigation techniques, in flight emergencies and how to deal with them, flight by sole reference to instruments, airfield night lighting and procedure and pre-flight decision making.
It may seem like a silly question but there is a legal definition for aviation purposes, and that is half an hour after sunset to half an hour before sunrise.