Tesco £4 LED lights
If you want to convert the tesco torch to red you can get gels and glass filters from most camera shops. Gels - or even sweet wrappers - will be better as you can cut it and tape it inside the housing.
Actually, anyone tried the lil 4 quid cycle lights they do.? I have just bought two white ones of these strange little "pods" with velcro fasteners. My god they're bright!!

I have wondered if they're 0.5 watt leds. They're at least as bright if not brighter than the Knog Frogs, though not as well made. I think they would need some silicone to seal them from the weather imo.