Supermarket fuel is the dregs left behind after the likes of Shell and BP have taken thier fill for thier tankers, Tesco,Sainsburys and Morrisons are examples of this, also the fuel is cheaper because they do not apply all of the additives as it costs more, so what you get is an inferior quality fuel which lacks the correct % of detergents, lead replacement chemicals and lubricant qualities that the major fuel companies apply. Use it regularly at your engines peril!
