Brexit poses a risk for European Security as the highly institutionalised relations based on EU membership change, prevailing certainties seem to disappear, and trust has been lost. But as maintaining strong links and a close relationship on foreign and security policy is in the interest of France, Germany and the United Kingdom, smaller and more informal alliances between these key actors on European Security will gain importance. Jean-Pierre Maulny, Marius Müller-Hennig, Neil Melvin and Malcolm Chalmers provide perspectives from France, Germany and the United Kingdom on these alliances, including careful considerations regarding the institutional framework and governance, but also possible fields of cooperation.