I am another poor soul who mis-fuelled his car at Shell - due to their V-Max marketing. I used a pump which was coloured red, white and black to fill my diesel car. But the pump contained unleaded.

Shell wrote to me that "The predominant colours used for fuel grade branding on service stations across the U.K. industry are dictated by the relevant British Standards (BS EN228 and BSEN590)".

These standards recommend that unleaded pumps are coloured green. Those standards also quote that the lettering must be at least 15mm high, and ideally larger. Shell's was 12mm high. There are other parts of BS EN228 with which Shell fail to comply.

But they sent me a dismissive letter saying that "Shell complies with all legal obligations for marking and labeling fuel pumps". Does this mean that trading standards have no legal basis? Even it they don't, Shell appear to be misrepresenting their position.