The U.S. and its allies across the Atlantic must forge a technology partnership and win the artificial intelligence race even as China makes steady advances, the U.K.¡¯s envoy in Washington said.

Ambassador Peter Mandelson warned of the consequences if China continues to get ahead in AI and other key technologies.

¡°They will be able to do things which cascade down not just to their own country but everyone else¡¯s across the world,¡± Mandelson said at an event hosted by the Atlantic Council in Washington on Tuesday. ¡°There is nothing I fear more in this world than China winning the race for technological dominance.¡±

Before being appointed ambassador, Lord Mandelson had criticized the Conservative-led government for mismanaging ties with China and called for a thaw in relations. He is a founder of Global Counsel, a firm that¡¯s become one of the most influential advisory groups in the U.K. and has been expanding its coverage of China.

The Labour government under Prime Minister Keir Starmer has been pursuing closer ties with Beijing despite unease in Washington and other U.K. allies.

Mandelson said U.K.-China relations are unlikely to return to where they were a decade ago.

¡°We¡¯re not going to to back to the ¡®Golden Era¡¯ of Cameron,¡± he said, referring to former Prime Minister David Cameron, whose government hosted Chinese President Xi Jinping in 2015 in a visit hailed as a breakthrough in ties.

Since then, London¡¯s relationship with Beijing has deteriorated over a crackdown on pro-democracy protests in Hong Kong, its support for Russia¡¯s war in Ukraine, and alleged cyberattacks and spying operations in the U.K.

Mandelson also cautioned the European Union to be ¡°much more skeptical¡± about building closer ties with China, even as the two sides step up their engagement to push back against the Trump administration¡¯s tariffs.

The ambassador called for a ¡°reboot¡± of the trans-Atlantic alliance not only in technology but also defense, pointing to the war in Ukraine as a ¡°brutal wake-up call.¡± He said European defense needs to step up and become less dependent on the U.S.

NATO leaders are expected to sign off on a new defense spending goal during their summit in The Hague next month, with U.S. President Donald Trump demanding an increase to 5% of GDP.

¡°We have lived in a fantasy created by the U.S. security guarantee, complacent that a friendly heavyweight across the water would be always there when the going gets tough,¡± he said.