These guidelines were put together by the Institute of Chartered Accountants at the request of the London Stock Exchange in order to inform directors of their obligations toward internal control as specified in the Combined Code. The Code states that "the board should maintain a sound system of internal control to safeguard shareholders' investment and the company's assets".
Turnbull's recommendations were that directors detail exactly what their internal control system consisted of, regularly review its effectiveness, issue annual statements on the mechanisms in place, and, if there is no internal audit system in place, to at least regularly review the need for one.
