While British officials stressed on Monday that there was no change to London’s policy on Iran, they said joining the US is the most significant non-Brexit foreign policy move to date of the newly-appointed Prime Minister, Boris Johnson.
Just two weeks ago, Britain was calling for a European-led naval mission. Now, it has joined what it said was a US-led “international maritime security mission”.
No other countries are yet involved.
“It is vital to secure the freedom for all international shipping to navigate the Strait of Hormuz without delay, given the increased threat,” said British Defence Secretary Ben Wallace.
“The deployment of Royal Navy assets is a sign of our commitment to our UK-flagged vessels and we look forward to working alongside the US and others to find an international solution to the problems in the Strait of Hormuz.”
The US Department of Defense welcomed the British decision.
“This is an international challenge and we look forward to the opportunity to work together with the Royal Navy and with additional partners and allies who share the common goal of ensuring the free flow of commerce,” Commander Rebecca Rebarich, a Pentagon spokesperson, said in a statement.
Tanker traffic through the Strait – through which a fifth of the world’s oil passes – has become the focus for a standoff between Iran and the US, which has beefed up its military presence in the Gulf since May.
Last month, Iran’s Islamic Revolutionary Guard Corps seized a British tanker, Stena Impero, near the Strait of Hormuz for alleged marine violations.
That came two weeks after Britain seized an Iranian oil tanker near Gibraltar, accusing it of violating sanctions on Syria.
Britain repeatedly ruled out any exchange and has since been giving UK-flagged vessels in the region a naval escort.
The tanker dispute has tangled the UK in the diplomatic differences between the European Union’s big powers – which want to preserve the Iran nuclear deal – and the US which has pushed for a tougher policy on Iran.
“Our approach to Iran hasn’t changed,” said British Foreign Secretary Dominic Raab. “We remain committed to working with Iran and our international partners to de-escalate the situation and maintain the nuclear deal.”
A British source was quoted as saying by the Reuters news agency that the focus of the new mission would be protecting the security of shipping and Britain would not be joining US sanctions against Iran.
Another British source said London hoped the US-led mission would transition towards a European-led mission. The UK has also offered to lead one of the US-led mission’s maritime task groups.
European nations have been reluctant to take part in the US naval mission.
On Monday, German Foreign Minister Heiko Maas reiterated that Germany would not join the mission in the Strait of Hormuz, adding that Berlin favoured a European mission but warned it was difficult to make progress on that.
“At the moment, the Britons would rather join an American mission. We won’t do that,” Maas told reporters.