That's Tesco for you. The cheapest option is to filter used oil from your local chippy. It's illegal though unless you pay the tax.

http://news.bbc.co.uk/1/hi/wales/2312521.stm

Yes, the taxes are high in the UK, but that was not my point. The tax on a litre of diesel is apparently the same as that on a litre of unleaded, as I have managed to find out after making my original post. So it appears to be the fuel companies ripping us off for diesel as it is cheaper for them to produce than petrol.

As for cooking oil, yes my car probably could run on cooking oil, but I don't want to run it on that. Besides, out of 21 cooking oils listed on Tesco.com the cheapest is £1.06 per litre, which is more expensive than diesel - even with the tax!!!!

Luxembourg has always been cheapest. They undercut their neighbours to get a little extra custom coming across their borders but if you go outside Europe, it's possible to buy a gallon for the cost of a litre here. I can remember a promise many years ago to keep diesel prices lower than petrol. The thing is that governments like to have lots of money to spend and they've been able to keep adding a penny or two to fuel taxes every year without much complaint, until recently.

It costs more to produce a litre of cooking oil in the supermarket than to get a litre to the fuel pumps but it's the taxes that make car fuel expensive.

A quick look on petrolprices.co.uk tells me that in my area the cheapest price for unleaded is 87.9p/litre and for diesel it is 96.9p/litre. I have to ask why diesel is 9p a litre more expensive in the UK than unleaded, when the opposite is true in most (if not all) other EU countries!

I have recently been travelling from the UK to Luxembourg on business. The prices on the other side of the channel are the opposite way around, with diesel cheaper than unleaded and it is the same whether I fill up in France, Belgium or Luxembourg. Luxembourg is the cheapest with me paying 86.9 euro cents for a litre of Shell V-power. Standard diesel being around 79.9 euro cents per litre.

So why the great diesel rip off in the UK? Is it the fuel companies. or the government or the retailers ripping us off? And more importantly, why are we letting them get away with it?

Fact: Diesel is cheaper to produce than petrol as it is far lower down the refining process, so it should be cheaper to buy!