Sovereign wealth funds based overseas own more than 10% of the UK stock market, according to Sir David Walker, the former banker and influential government adviser. This makes SWFs a powerful new shareholding bloc with an important role to play in corporate governance.

Information about the holdings of often-secretive sovereign funds is hard to come by, but the Norwegian Government Pension fund, one of the most open, said that at the end of March its ownership of global equity markets was close to 0.9%.