Exxon Mobil is working to reopen one of Britain’s main underground fuel pipelines after the discovery of a tapping device and a stash of diesel that police believe was siphoned off by thieves. The company, which operates as Esso in Britain, said on Tuesday that the device was found on the Midline pipeline that transports fuel from its Fawley Refinery near the south coast to its Birmingham fuel terminal in central England. « Our specialists are now working to remove the tapping device and repair and test the pipeline and restore it to normal operations as soon as possible, » Exxon said in a statement. Fuel tapping from pipelines is a major problem in countries such as Nigeria, costing billions of dollars a year, but is virtually unknown in Britain. Police launched an investigation on Thursday after a large quantity of diesel was found in an industrial storage unit at West Wellow in Hampshire, southern England. Media reported that more than 30,000 litres of diesel was involved, worth 41,000 pounds ($70,000) at pump prices. Police said on Monday that they had arrested two men, aged 32 and 34, in connection with the theft. Exxon said on Tuesday that there has been no product leaks and it does not expect retail customers to be affected by the pipeline closure because it has made alternative supply arrangements. While fuel tapping from UK pipelines is rare, media have reported a small but growing number of fuel thefts from vehicle tanks. The theft of metals, such as copper cable, has led to communications and rail network disruptions.