In the handbook and possibly the fuel flap it will say to use fuel that only meets BS EN590. All diesel sold in the UK has to meet the requirements of BS EN590. All cars sold are designed to run on BS EN590 diesel.

We have been using Supermarket fuel almost exclusively since the mid 80's and have never had a problem. We only fill with branded fuel if its more convenient or we are on holiday, no supermarkets within 30 miles of our lodge. I can honestly state that none of our cars has driven better or done more mpg on branded instead of supermarket.

The days of seeing BP or Shell tankers emptying their contents into a supermarket filling station seem to be over, but it doesn't mean the liquid inside them isn't the same.

A few months ago a fuel tanker pulled off the Total forecourt down the road from us. I followed it into town and it pulled into the Asda filling station. Asda was 4 pence a litre that day for fuel from the same tanker.

In the UK as many others have said I have never found any real discernable difference in diesel.

However in France I noted a very marked drop in MPG when I used ultra cheap Carefour supermarket diesel as opposed to Regular Shell diesel from normal roadside filling stations.

The days of seeing BP or Shell tankers emptying their contents into a supermarket filling station seem to be over, but it doesn't mean the liquid inside them isn't the same

Tankers have more than one compartment & the fuel that is dispensed into them will have various lotions & potions added just before it is dicharged.

The way supermarkets are making more from their fuel or the reason they can sell it cheaper is the proportion of biodiesel that is added. This attracts less duty than fossil fuel diesel so the more BD you have the less duty you pay, but if you charge the same the balance is proffit.

Any diesel engine say >10 years old will run on anything, >2 <10 a little less so & <2 more care is needed in freezing temperatures. This is more applicable to the Euro V engines.