Diesel prices have hit another unwanted milestone for motorists up and down the country as a tank of fuel now costs £100. Motorists with a standard family car, which contains a 55-litre tank, filling up with diesel will now face a staggering £100 charge at the pumps. The price of diesel is rapidly growing, with RAC Fuel Watch analysis showing that prices are rising by 0.35p per day. Diesel drivers are facing soaring fuel prices, with an average tank now costing £100 | GETTYPetrol prices are at their highest price since the start of the war, despite falling to their lowest point less than a month ago. GB News has compiled the most expensive petrol and diesel prices seen across the UK so far in August, using Fuel Finder data.