Conducting exercises is one of our most important tools for strengthening our capacity to manage accidents and crises. Together, in the safe environment provided by exercises, actors have the opportunity to test their plans, their actions and their organisations in an imaginary crisis situation, without the risk that any missteps lead to anyone’s being injured, or to any other serious societal consequences. Experience from major events of recent years shows the need to develop collaboration. Looking to the future, we see that exercises will increasingly focus on civil defence and heightened preparedness, thereby providing support in the revival of planning total defence. Deriving the benefit of the lessons provided by collaboration exercises, especially those that are cross-sectoral, is going to be even more necessary.