Is there a “universal” fuel card that can be used at any or all petrol stations in the UK?

Unfortunately no  fuel card provider offers fuel cards that can be used at all petrol stations. But you can check with a few major suppliers and get a good deal for your business: just answer a few simple questions about your needs and where you operate and you will get free quotes from fuel card suppliers. Then it’s just a matter of selecting the one with the best network coverage of stations.