The UK is to increase its military presence in the Gulf by sending a second warship to the region.
HMS Duncan, a Type 45 Destroyer, will sail to the Gulf in the coming days after recently completing NATO exercises in the Black Sea, and is expected in the region shortly.
Duncan will operate alongside the Royal Navy frigate HMS Montrose, and US allies in the Gulf, but she will not be part of an international maritime coalition proposed by Washington.
The Ministry of Defence would not comment on the deployment, but it is understood that Duncan was always due to travel to the region to give some relief to HMS Montrose.
However, her deployment has been brought forward as a result of the deepening crisis with Iran.
Foreign Secretary Jeremy Hunt said it was time for cool heads, adding: We want to do everything we can to make sure that we don’t have an unintended escalation which could be very dangerous for the world.
In addition to HMS Montrose, the UK also has four mine hunters permanently stationed in the region, and a Royal Fleet Auxiliary ship.
It comes after a senior Iranian cleric warned Britain will soon be slapped in the face for daring to capture an oil tanker last week off the coast of Gibraltar.
Kazem Sedighi made the remarks after Tehran demanded the immediate release of the seized supertanker Grace 1, warning the UK: This is a dangerous game and has consequences.
Iran’s strong establishment will soon slap Britain in the face for daring to seize the Iranian oil tanker, cleric Kazem Sedighi told worshippers during his Friday prayer sermon in Tehran.
Tensions are mounting in the Gulf after a Royal Navy warship deterred Iranian patrol boats attempting to impede a British tanker sailing through the Strait of Hormuz on Thursday.
Prime Minister Theresa May’s official spokesman has said discussions are ongoing between UK and US about increasing their military presence in the Gulf.
The Grace 1 tanker was seized last week after it was suspected of taking crude oil to Syria in breach of EU sanctions.
Calling for its release, a spokesman for Iran’s foreign ministry told the state news agency IRNA: This is a dangerous game and has consequences.
The legal pretexts for the capture are not valid… the release of the tanker is in all countries’ interest.
Iran’s foreign minister Mohammad Javad Zarif accused the UK of being servants of America and said the EU sanctions were intended to stop Europe buying Syria’s oil, not countries on other continents.
This is a very childish and ridiculous excuse by the British, he said.
They should officially announce that we are servants of America and act on behalf of America. America has returned their favour well by insulting their ambassador and their prime minister.
Mohammed Marandi, a professor at Tehran University, claimed the seized Iranian tanker was too big for Syrian ports so could not have been carrying cargo to the war-torn country.
He told Sky News: The whole notion that Europeans have the right to strangle nations to get their way is something that people in this part of the world view very differently than in Europe.
Iranians see this as an act carried out at the behest of the United States.
However, Gibraltar has insisted its decision to detain the Iranian tanker was taken alone and not on the orders of the UK government.
The territory’s chief minister said Fabian Picardo said: There has been no political request at any time from any government that Gibraltar should act or not act on one basis or another.
The vessel contained 2.1 million barrels of light crude oil, he added.
The UK government said on Thursday that three Iranian vessels tried to block a British-owned tanker passing through the Strait of Hormuz, which controls the flow of Middle East oil to the world, but backed off when confronted by HMS Montrose.
Iran’s Revolutionary Guard denied claims of a confrontation, saying if it had received orders to seize any ships it would have executed them immediately.
Sky News understands British ships have been warned to keep alert for Iranian patrol boats being aggressive towards them.
Some 15 to 30 British-flagged tankers and other large ships are in the Persian Gulf on a daily basis. Between one and three pass through the Strait of Hormuz every 24 hours.
Mr Hunt said he will add more warships to Britain’s fleet if he wins the Tory leadership race and becomes prime minister.
He has vowed to increase defence spending from 2% of GDP to 2.5%, a cost of around £12bn more a year in 2023, and more jets for the navy’s new aircraft carriers could be included.
When you look at this week’s events it shows that in recent decades we have run down the navy too much, he wrote in the Daily Telegraph.
Police in Gibraltar have arrested the captain of the Grace 1 and the chief officer of the vessel.
Iranian President Hassan Rouhani has previously warned the UK of consequences after the seizing of its oil tanker.
Meanwhile, the US is pushing allies to increase their maritime security in the region, safeguarding strategic waters off Iran and Yemen.
Relations between the US and Iran have fractured since President Donald Trump pulled the US out of a nuclear deal with Iran and re-imposed sanctions.