Came accross the Skip Bag a couple of weeks ago and bought one for my garden waste, hedge clippings etc, it is great. It is like one of those 3ft x3ft x3ft bags that people get building materials delivered in. It is brilliant for bulky light weight objects to take to the local tip, fill it up, make sure you can still lift it into the car, take it to the tip, heave the contents over the side and bring it back to be re used, it does tend to be a 2 person job 'cos of its size though.
If you have a small amount of stuff to get rid of you can contact Hales and for £30 or so they take your Skip Bag of debris away if you are in their operating area...
http://www.skipbag.co.uk
It is also cheaper than the silly little bags most DIY/Garden centers sell for rubbish!

think I saw these for sale in Jewson's ...