His fellow Irishman, Tullow's finance director Tom Hickey, also used to be an accountant - for the now defunct Andersen, which audited the books of the collapsed US energy trader Enron. "I wasn't as smart as Tom to join Andersen," Heavey jokes. But in the week that oil prices hit new record highs, Tullow is looking pretty smart, with a market value of £755m. Having bought Energy Africa, it has more than doubled its production to 54,000 barrels a day overnight. Heavey admits the deal was a gamble. But he has a good track record of betting big - and winning.