Britain is focused on "supporting the political process" between Washington and Tehran, Sir Keir Starmer has said, as tensions escalate over the potential use of British air bases for US military action against Iran.
The government is believed to be resisting Donald Trump's request to utilise the Diego Garcia base in the Chagos Islands, citing concerns over international law.
This comes as the US president threatened military intervention against the Islamic Republic should a nuclear agreement fail.
Separately, the Prime Minister underscored the UK's commitment to diplomatic solutions during a call with Saudi leader Crown Prince Mohammed bin Salman.
A Downing Street spokesperson said: “On Iran, the Prime Minister emphasised the UK’s focus remains on supporting the political process ongoing between the US and Iran.
“He added that Iran must never be able to develop a nuclear weapon and security in the region must be a priority.”
High-stakes talks between the US and Iran on curbing Tehran’s nuclear programme ended without an agreement on Thursday.
The US has amassed a fleet of aircraft and warships in the region.
Mr Trump withdrew his backing for Sir Keir’s Chagos Islands deal to hand sovereignty of the islands to Mauritius because the UK has not approved the use of the joint UK-US Diego Garcia military base to strike Iran.
Reports say that both the US and Iran plan to resume negotiations soon after consultations in their countries' capitals.
Techical-level discussions are scheduled to take place next week in Vienna, Omani Foreign Minister Sayyid Badr Albusaidi said in a post on X after the day's talks ended in Switzerland.
Any substantial move toward an elusive agreement between longtime foes Washington and Tehran could reduce the imminent prospects for U.S President Donald Trump to carry out a threatened attack on Iran that many fear could escalate into a wider war.
