In 1994, Ukraine surrendered the world's third-largest nuclear arsenal, inherited from the collapsed Soviet Union, in exchange for security assurances from the US, Russia, and the UK.

Ukraine’s denuclearisation is often considered a huge success story in nuclear non-proliferation, but in retrospect, it may have paved the way for Putin's 2022 invasion.

As talk of US-European security guarantees for Ukraine resurfaces in the context of tentative Russia-Ukraine peace talks, we speak with BBC Paris correspondent Andrew Harding about the history of the 1994 agreement, and consider whether Ukraine would ever again believe promises made to protect it.

Producers: Sam Chantarasak and Xandra Ellin

France's President Emmanuel Macron (R) and Ukraine's President Volodymyr Zelensky arrive to chair the Coalition of the Willing Summit, at the Elysee presidential palace in Paris, on September 4, 2025. Ludovic Marin/ Getty