General Motors' board yesterday caused shockwaves in the motor industry when it announced it would retain its Vauxhall and Opel car businesses and cancel the planned sale to Canada's Magna and Russia's Sberbank.

The U-turn, announced after a six-hour board meeting, will be seen as an embarrassment for the German government, which spent months negotiating a €4.5bn (£4bn) aid package to facilitate the sale to Magna.