Good news for caravanners and motorhome users! Asda, Tesco and Sainsbury's will be selling a litre of diesel for less than £1 from today. It'll mean the average family sized diesel car will be over £10 better off each time they fill up, compared with last year. Petrol prices have remained around the £1 mark since dropping early last year, meaning whatever fuel your motorhome or tow car uses, you'll be quids in! Now you just have to decide what to spend the savings on...