In my last article about fuel prices, I highlighted just how much of the pump price goes to the Treasury.

I’m afraid that this time the news is equally bad!

May has seen the highest rise in diesel prices ever recorded, according to the latest fuel price report from the AA.

Diesel rose by an average of 6.76p per litre from 117.41p to 124.17p between mid-April and mid-May. This means that the 68 litre fuel tank on my Transit now costs an extra £4.60 to fill up. For vehicles with a smaller 50 litre tank, the cost of a tank full of diesel is up by £3.38.

Most of this increase has taken place in the first half of May, but it is interesting to see how the price differences between supermarket garages and non-supermarket garages have grown. Supermarket garages are now an average of 2.5 pence per litre cheaper for petrol and a surprising 4p per litre for diesel.

Surprising to me, anyway! The pump prices at my local Sainsbury and Morrisons are pretty much the same price as the Shell garage I usually use, although some other local forecourts are more expensive than the supermarkets.

Unsurprisingly, London is still the most expensive place to buy fuel and Yorkshire & Humberside the cheapest.

As the AA comments, the most worrying aspect of this is that the rise in oil prices appears to be primarily the result of speculative investors putting money into oil in an attempt to make a quick buck from the rising prices.

The old ‘rising demand, limited supply’ argument is being trotted out by those with vested interests, but the facts appear to suggest that increased demand for oil is not the real culprit (remember when people were saying that house prices had to rise because there weren’t enough houses?).

I’m going to stick my neck out and predict that oil prices will start to fall in the next six months – but I will also predict that petrol and diesel prices won’t fall as far…

Anyone care to disagree?