A private bank has seen growing numbers of senior executives wanting to take out "jumbo loans" of more than £1m ($2.01m) to buy shares or make investments since the start of the global stock market turmoil.

Investec Private Bank, which is part of the South African bank, extends personal £1m-plus loans to senior executives and company founders which are used to fund share purchases in their own company or make an investment in an unquoted company. These loans are often secured against the directors' personal wealth as collateral - such as property or share portfolios.