During a surprise visit to Kyiv, UK PM Keir Starmer and Ukrainian President Zelenskyy signed a "100-Year Partnership" treaty emphasizing military support amid uncertainties over U.S. aid under President-elect Trump. The agreement includes provisions for enhanced military cooperation, economic reconstruction, and a mobile air defense system, affirming Britain's long-term commitment to Ukraine. Starmer's visit showcased a strengthening of ties as Ukraine faces ongoing aggression from Russia, with Zelenskyy urging continued Western support. The partnership is set against the backdrop of shifting dynamics in U.S.-Ukraine relations with Trump returning to power.