iMac G5 OS X 10.5.8 - still works, how do I recycle it in the UK?

After more than 5 years sitting used in a box room collecting dust, I just turned on my iMaC G5 and was shocked how quick it performed.

I have reformatted the hard drive and updated the software as much as it will allow.

Now I need to sadly get rid of it as I do not have any use for it or have the space.

It's still very useable for surfing the web and email etc, can I give this away.

Would anyone want it or is there a way I can recycle it?

Seems such a shame as it still works, any ideas would be appreciated.