Being forced to disclose an accounting black hole in a company mere months after the Enron and WorldCom scandals would be filed by most people under the heading, "things to avoid".

Pity Ian Robson then. In April 2003, the finance director of Ashtead Group, which rents large equipment such as excavators, generators and forklift trunks to construction contractors as well as smaller items to homeowners, was on holiday when he learnt that the controller of US subsidiary Sunbelt Rentals had inflated the previous year's figures. "He took it upon himself to misreport the numbers. My vacation was swiftly terminated," Robson says.