President Emmanuel Macron and UK Prime Minister Keir Starmer signed the Northwood Declaration on 10 July, pledging for the first time to coordinate the use of their countries’ nuclear forces. The statement says there is “no extreme threat to Europe that would not prompt a response by both nations,” while stressing that France’s and Britain’s arsenals remain under separate national control. The accord creates a Franco-British Nuclear Steering Group to align policy, early-warning data and exercises, deepening cooperation first set out in the 2010 Lancaster House treaties. Officials framed the move as a signal to Moscow and a reassurance to European allies amid questions over future US security guarantees. Britain is estimated to possess about 225 warheads and France roughly 290, giving the partnership a combined stockpile of more than 500 nuclear weapons. Alongside the nuclear pact, Defence Minister Sébastien Lecornu confirmed that MBDA will restart full-rate production of the Franco-British Storm Shadow/SCALP-EG air-launched cruise missile in 2025, ending a 15-year hiatus. Paris has placed a new order to replenish stocks depleted by deliveries to Ukraine and to support the next phase of the joint Future Cruise/Anti-Ship Weapon programme. Taken together, the nuclear coordination agreement and the missile production restart underscore a broader push by Europe’s two nuclear powers to assume greater responsibility for the continent’s defence and to modernise their high-end strike capabilities.