James Gorman, the head of Morgan Stanley, has become the latest bank chief executive to fall victim to the financial services email prankster, as concern grows about about email security at the institutions.

Pretending to be the former UK chancellor Alistair Darling, who also sits on the board of Morgan Stanley, the prankster sent Gorman an email addressed to a fake journalist with a photo of Darling attached. He quickly followed this up with another in which he apologised for emailing the "wrong" person.