One of Morgan Stanley’s most senior London-based investment bankers has quit, with his resignation revealed on an internal conference call made just days after new chief executive James Gorman took the reins at the firm.

John Hyman, co-head of global capital markets at Morgan Stanley, resigned from the US bank last month. However, Hyman's departure was only announced on an internal conference call on Monday, just three days after Gorman officially took over the running of the firm from former chief executive John Mack.