because recycling is essential when you're living on a finite planet with 6 billion or so humans to move around
At the moment, there is a clouded, complicated process, whereby if you want to run your diesel engine on recycled chip oil, you have to 'announce' this to the revenue and customs authority, who will then oversee your production, and tax you at a rate as high or higher than normal petrol….. this country is tangled in inefficient systems of bureucracy, thats why it takes so long for things to happen / change
Biodiesel can be made at home out of used chip oil with inexpensive filtration equipment. My suggestion would be to forget about taxing it – it is a very useful form of recycling and should be encouraged as much as possible, so links can be made between chip shops and car owners…
and if you really do insist on taxing it to lift your backsides out of your deficit, tax it at the point of sale between chip shop owners (and other industries that use large amounts of cooking oil) and car owners / biodiesel producers. This way the chip shop owners would have one more thing to sell, and they could advertise this in their shops…. "make your own biodisel! 30p a litre!", or something similarly attractive. Even if the tax would be 50%, the chip shop owner is still making 15p per litre on something they would otherwise throw away….