The United Kingdom has moved to calm escalating transatlantic tensions after Washington threatened sweeping tariffs tied to its push for control over Greenland, with Prime Minister Keir Starmer warning that economic retaliation would only deepen the crisis.

Speaking after an emergency government briefing, Starmer said London would not respond with counter-tariffs, despite the U.S. signaling it could impose a 10 percent levy on British and European goods starting February 1. The proposed measures would rise sharply by mid-year unless U.S. demands over Greenland are met.

Starmer framed the dispute as a test of alliance cohesion, stressing that economic pressure between NATO partners undermines collective security rather than strengthening it.

“A trade war would hurt ordinary people first,” Starmer said, pointing to businesses, workers, and households that would bear the cost of escalating tariffs. He added that disputes among allies should be resolved through dialogue, not economic coercion.

The tariff threat targets several U.S. allies, including Denmark, Norway, France, the Netherlands, Finland, and the U.K. It is linked directly to Washington’s assertion that acquiring Greenland is a strategic necessity for American defense, a position that has alarmed European capitals.

European officials have privately warned that such tactics risk fracturing long-standing security partnerships. Denmark, which maintains sovereignty over Greenland, has emphasized that the territory’s future cannot be decided through economic pressure.

Behind the scenes, European leaders are weighing potential responses if negotiations fail. One option under discussion is the European Union’s anti-coercion framework, which allows Brussels to restrict market access for countries using trade pressure to influence political decisions. Any move in that direction could expose tens of billions of dollars in U.S. exports to retaliation.

Starmer, however, signaled that Britain’s priority remains de-escalation.

“The use of tariffs against allies is not the right path,” he said, reaffirming the U.K.’s commitment to NATO, international law, and diplomatic engagement. He emphasized that strengthening Greenland’s security should be addressed cooperatively, not used as justification for economic threats.

The standoff comes at a sensitive moment for global trade, with governments already navigating fragile supply chains and slowing growth. Analysts warn that injecting territorial disputes into trade policy could unsettle markets and weaken trust among allied economies.

For now, London is betting that restraint and diplomacy will prevent the dispute from spiraling into a broader economic confrontation, even as pressure mounts across Europe to prepare for a harder line if talks collapse.