bp ultimate diesel is the best in my opinion, as its got the highest cetane rating - its just bloody expensive.
burns better than any other, cleans and reduces smoke -
check there website for facts.however i now run on shell standard diesel, as bp ultimate is far too expensive now. and i havent noticed any power loss and im still getting the same mpg.
i use forte diesel treatment every 7000 miles as reccomended to me by brother whos a mechanic, this cleans the entire fuel system, valves etc and reduces emissions- (just add contents to three quarters of a tank of diesel - not a full tank as they suggest - its more concentrated this way)
i have been told that supermarket fuels come from the total/elf/greenergy refinerys at lincoln and pembrokeshire? so is say sainsburys/tesco etc diesel the same as total or elf diesel?

- it probably is though.
makes you wonder because there are only about 9 or 10 refinerys in the country.