Lord Hermer is likely to have been involved in the Government’s decision

Britain has stopped sharing intelligence with the US about drug trafficking in the Caribbean, in a move that risks opening a fresh rift with Donald Trump.

In a major break with its closest ally, the Labour Government allegedly paused intelligence briefings because it does not want to be complicit in US strikes on suspected drug boats in Latin America, CNN reported.

The pause came into effect in September shortly after the US began carrying out lethal strikes against boats suspected of transporting drugs from Latin America to mainland US, sources told the news outlet.

British officials are said to have grown concerned that the US could use intelligence they had provided to identify targets for strikes, which they fear could be in breach of international law.

Lord Hermer, the Attorney General, is likely to have been involved in the Government’s decision.

In June, the Government’s top legal adviser was reported to have raised concerns about the legality of the UK joining Israel’s bombing campaign against Iran. He is also said to have played a key role in the deal that saw the Government sign a deal to hand the Chagos Islands to Mauritius.

The UK has long flagged vessels suspected of carrying drugs to the US coast guard.

Mr Trump’s administration has faced growing calls from allies to end its bombing campaign against suspected drug boats, which have so far killed at least 75 people.

Mr Trump has justified the strikes by saying the United States is in “armed conflict” with drug cartels and claiming the boats are operated by foreign terror organisations that are flooding America’s cities with drugs.

The Trump administration has provided no evidence for its claims and has faced growing pressure from politicians, including Republicans, to release more information on who is being targeted and the legal justification for the strikes. Information has typically been sent to Joint Interagency Task Force South, which is based in Florida and works with partner nations to reduce the illegal drug trade.

Vice Admiral Bob Cooling, the former assistant chief of naval staff in the Royal Navy, said any such decision could have a significant impact on US-UK relations.

The retired British naval chief told The Telegraph: “It would be absolutely extraordinary if this was the case… it would be huge. “The US-UK intelligence link is unparalleled anywhere on the globe and goes back to just after the Second World War.

“It’s deep and persistent and really open and transparent. Any breach of that openness would be resisted by both parties strenuously because it’s so important for both of us.”

Gen Sir Peter Wall, a former chief of defence staff, added: “This would be exactly the sort of consequence that could occur from prioritising human rights over the wider national interest.”

The British Government is said to agree with Volker Türk, the UN’s human rights chief, who said last month that the strikes amounted to “extrajudicial killing”, sources told CNN.

Canada has also distanced itself from the strikes, telling the news outlet that it will continue its partnership with the US coast guard, called Operation Caribbean, but has made clear it does not want its intelligence being used to help target boats.

On Monday, Pete Hegseth, the US defence secretary, announced the latest strikes in the eastern Pacific Ocean on two vessels suspected of ferrying drugs. Six people were killed in the blast.

The Trump administration’s campaign against drug trafficking in South American waters is seen by many as a pressure tactic on Nicolas Maduro, the Venezuelan president, whom he has called to be deposed.

“These vessels were known by our intelligence to be associated with illicit narcotics smuggling, were carrying narcotics, and were transiting along a known narco-trafficking transit route,” Mr Hegseth posted on social media.

The strikes began in early September and have targeted vessels largely in the Caribbean Sea but have increasingly shifted to those in the eastern Pacific, where much of the cocaine from the world’s largest producers is smuggled.

The Trump administration also has built up a massive military force in South American waters, including ordering an aircraft carrier to the region.

The US State Department and the British Foreign Office were approached for comment.