Russia could reinvade Ukraine without US security guarantees, Starmer warns

UK prime minister faces major diplomatic effort to get president on board after he said no plans for US backstop'

Keir Starmer has warned that Vladimir Putin could invade Ukraine again unless the US provides security guarantees as he arrived for critical talks with Donald Trump at the most precarious moment for European stability in decades.

With the future of Ukrainian security hanging in the balance, he urged the president to commit a US backstop to a British and French-led peacekeeping force, saying it was the only way to avoid Russia plunging Europe back into war.