By Levi Winchester The cheapest and most expensive petrol stations in the UK – with Morrisons found to have the lowest price for fuel. Morrisons charged an average of 136.9p a litre for petrol and 145.5p for diesel on Thursday, according to the RAC Foundation. But the most expensive was found to be Shell, where it cost an average of 142.6p a litre for petrol and 151.2p for diesel. The figures suggest filling a 55-litre family petrol car is typically £3.14 cheaper at Morrisons compared with Shell. Supermarket fuel stations remain the cheapest overall to fill up, but drivers are urged to still s…