A common refrain in the City of London is that finance directors make the best boardroom chairs. They are seen to have smaller egos (at least compared with some table-thumping chief executives), an attention to detail, an understanding of risk management and an intense focus on the bottom line.

But these days chief financial officers (CFOs) are also increasingly tapped for the CEO role – from Ms Margherita Della Valle at Vodafone to Mr Murray Auchincloss at BP, who both got the top job at a time of upheaval at their companies. As ever, when a crisis hits, call the numbers guy or gal.