When he was a trainee accountant, Ian Powell was sent to audit an oil storage depot in the Midlands. On a bitterly cold night, he had to clamber to the top of a dozen rail tankers to check oil levels with a dipstick. But something did not feel right.
Mr Powell, now chairman of the UK unit of PwC, the professional services firm, noticed that certain tankers were riding higher on their springs than others. This suggested a lighter load – yet his readings did not indicate that they contained less oil. “I couldn’t understand why,” he recalls.
The resulting investigation revealed that someone had defrauded the depot. In some tankers, a hidden cylinder – a tank within a tank – had been fashioned around the hole where the dipstick was inserted in order to overstate how much oil was inside.