Prime Minister Sir Keir Starmer "set out his position on Greenland" during a phone call with Donald Trump on Wednesday evening, Downing Street has confirmed.
While specific details of Sir Keir’s comments were not provided, the discussion follows suggestions from US officials that America could potentially use "military means" to acquire the semi-autonomous Danish territory.
Trump has previously claimed the island is crucial for US national security.
Starmer has repeatedly stated that Greenland’s future must be determined solely by its own people and Denmark, a stance he reiterated in the Commons earlier the same day.
The ongoing controversy surrounding Greenland has cast a shadow over relations between the United States and Europe, with Denmark’s prime minister warning that a US takeover would spell the end of the Nato alliance.
US secretary of state Marco Rubio had earlier said Mr Trump was examining how to “acquire Greenland”, suggesting the US could offer to buy the territory but adding it “retains the option” to use force.
But writing in the Spectator, Lord Peter Mandelson, who was sacked as ambassador to the US last year over his connections with the paedophile financier Jeffrey Epstein, accused European nations of engaging in “histrionics about Greenland” due to their “growing geopolitical impotence”.
Arguing that Mr Trump was not going to “invade” Greenland, he dismissed concerns about sovereignty and Nato’s future as “performative” and called for a “considerably beefed-up role” for America in the territory to counteract threats from Russia and China.
Sir Keir’s call with Mr Trump comes as Deputy Prime Minister David Lammy prepares to meet US vice-president JD Vance on Thursday.
The meeting, at which Greenland is likely to feature, forms part of Mr Lammy’s visit to the US to mark the 250th anniversary of America’s declaration of independence from Britain.
The two men are long-standing friends, and Mr Lammy hosted Mr Vance and his family last year at Chevening, his grace-and-favour house in Kent.
Wednesday’s call also saw Sir Keir and Mr Trump discuss the seizure of oil tanker Marinera earlier in the day, continuing negotiations on the future of Ukraine and US military action in Venezuela.
It is the first time the two men have spoken since US special forces seized Venezuelan president Nicolas Maduro and brought him to New York on Saturday.
Read MoreTrump says Venezuela will ‘only’ purchase American products with oil deal revenue