Kenneth G. L. Simpson is Managing Director of Engineering Safety Consultants Ltd and has been associated with safety related systems design and also with their assessment for over 40 years. He is a member of both the IEC61508 and IEC61511 drafting committees and the IGEM (SR15) panel, which writes the gas industry guidance. Following a career in aerospace, Ken has spent over 35 years in the control and safety system industry, has written a number of papers on the topic and gives frequent lectures.