Aldi have got these waterproof caps with 5 built in LED lights instore from Thursday 17/04/14 in either beige or green for £3.99 which seems like a cracking deal and you get batteries included as well. Just the job for night fishing etc.
Product Information :-
A water repellent, 100% cotton cap that's ideal for day or night-time fishing.
5 White LEDs on peak of cap
2 x CR2032 lithium button batteries included
Choose from: Beige or Green
One size, with Velcro® adjuster at back