Since the signing of the Lancaster House Treaties in 2010, the bilateral partnership between Paris and London has been a key axis for both countries’ involvement in Europe’s security and defence affairs. What impact can the result of the “Brexit” vote have on this rising partnership? This contribution argues that while the partnership will undoubtedly remain central in Europe, the two parties will in the future both face contradictory incentives. While London will have new incentives to invest in its relationship with Paris, it might also try to discourage further defence integration in the EU. On the contrary, France – which had been more forward leaning, and concerned with Britain’s lack of commitment to a bilateral relationship they considered central – will be tempted to look elsewhere. Indeed, the ambition for a militarily active European Union with a strong defence industrial base may prove contradictory with an investment in the bilateral partnership with London.