The Rockefeller family yesterday attacked ExxonMobil, the world's biggest listed oil company, for failing to recognise the need to move away from oil and gas into alternative fuels.

"We are trying to keep a giant from falling," said Neva Rockefeller Goodwin, economist and great-granddaughter of John D. Rockefeller, the founder of Standard Oil, which ultimately spawned today's Exxon.