The UK will not be involved in enforcing the US military blockade of Iran, the BBC understands.
British naval ships and soldiers will not be used to block Iranian ports, while UK minesweepers and anti-drone capabilities will continue operating in the region.
A spokesperson for the UK government said: "We continue to support freedom of navigation and the opening of the Strait of Hormuz, which is urgently needed to support the global economy and the cost of living back home."
The US announced the blockade after talks with Iran failed to secure a lasting peace deal to end hostilities in the Middle East, as Prime Minister Sir Keir Starmer urged "de-escalation" in the region.
After US and Iran negotiators met in Pakistan's capital Islamabad, President Donald Trump said the US would start "BLOCKADING any and all Ships trying to enter, or leave, the Strait of Hormuz".
