Cycling in the dark can be safe, as long as other road users see you.
You must have a white front, and a red rear light on, between dusk and dawn. It also encourages the use of reflectors on pedals.
Here are some mistakes to watch out for when cycling with lights:
1) Don’t accidentally cover your rear light with your coat
2) Don’t let the light run out of battery
3) Don’t go cycling without back up cycle lights
4) Don’t forget your lights in poor visibility conditions during day cycling
5) Don’t forget to take your lights off when chaining up your bike