Pound Shop Xmas Tree Hack: One Transistor LED Flasher with LDR

After buying a rather lifeless LED Christmas tree from the pound shop, I thought I'd liven things up with an LED flasher circuit. There are lots of different ways to flash an LED, from a single unijunction transistor all the way up to a PIC microcontroller. I've chosen a slightly odd circuit which uses one transistor and an LDR (light dependent resistor). Inspiration came from here: http://www.b-kainka.de/bastel29.htm