British companies are seeking deeper trade ties with Europe, business groups told CNBC, as U.S. President Donald Trump unveiled a sweeping 15% tariff on all imports after the Supreme Court struck down previous levies.

New tariffs would mark a 50% increase on the level negotiated last year in a trade deal between the U.K. the U.S., making the country one of the worst hit, according to analysis from think tank Global Trade Alert.

While U.S. Trade Representative Jamieson Greer said the administration “expects” to stand by trade deals, the U.K. government is reportedly in ongoing discussions with counterparts in America.

The seesawing uncertainty is increasingly forcing U.K. businesses to look to closer alignment with the European Union and European countries, as they hunt for predictable trade partnerships, groups which represent U.K. businesses told CNBC.

“There’s just no certainty or consistency and companies are very weary of this,” said William Bain, head of trade policy at the British Chambers of Commerce (BCC), which represents 50,000 businesses.