What is the difference between “gas oil” and diesel?

David Wardale has proposed that the 5AT be fueled with “gas oil“, saying it was “equivalent to diesel“. In fact, gas oil is diesel fuel but without the dyes which show it has had the road tax paid.

Note – the possibilities of using “greener” fuels in the 5AT are discussed in other sections of this website (with minor duplication of content) as follows: