Britain appears to be moving closer to U.S. President Donald Trump's position on Iran and hardening its attitude towards Tehran - the result, diplomats say, partly of talks during the American leader's recent visit to London, but also because of aggressive Iranian actions.
U.S. officials say they've been cheered by the stiffening of Britain's public rhetoric in support of Trump in the precarious standoff with Tehran.
They contrast that with British criticism of Trump's decision last year to pull out of a 2015 deal, co-signed by his predecessor Barack Obama, in which Tehran agreed to curb its nuclear program in return for sanctions relief. President Trump withdrew the U.S. from the agreement, citing concerns that Tehran had done nothing to curb expansionist behavior in the region and was still determined to eventually build nuclear weapons.
British officials had also bristled at Trump's reimposition of sanctions on Iran and had been searching with other European powers ways to circumvent the U.S. sanctions so they wouldn't impact European businesses.
Britain is still calling for a "de-escalation" in the Persian Gulf, but has been more forthright than France or Germany in condemning Iran for aggression in the Strait of Hormuz, including mining tankers and downing a U.S. drone - as well as for Tehran's threats to step up nuclear activities and to breach the cap on uranium stockpile limits set by the 2015 accord.
Britain's foreign secretary, Jeremy Hunt, said Monday he was worried an accidental war could be triggered, adding, "we are doing everything we can to ratchet things down."
Hunt said Britain is closely in touch with the United States over the "very dangerous situation in the Gulf" and is "doing everything we can to de-escalate."
But he did not rule out the possibility Britain would consider a request for military support from its "strongest ally," and would consider backing the U.S. in the Gulf "on a case-by-case basis." That might include greater British support in protecting shipping in the Strait of Hormuz.
Britain blames Iran for strains
And Hunt put the onus on Iran for the dramatic rise in tension.
"We do strongly believe that the solution is for Iran to stop its destabilizing activity throughout the Middle East and we are very concerned about the sabotaging of tankers that has happened recently, which is almost certainly Iran," he said.
Concern about a potential armed confrontation between the U.S. and Iran has mounted since Washington blamed Tehran for mine attacks on a pair of oil tankers in the Strait of Hormuz, the strategic sea passage between the Persian Gulf and the Gulf of Oman.
Tehran denies it mined any ships.
Last week, Trump said he had canceled a retaliatory airstrike against several Iranian targets, including anti-aircraft missile batteries, for the downing of a U.S. drone, on the grounds that it would have been disproportionate because of the loss of life it would entail.
But according to U.S. news accounts, Trump approved cyber-warfare disruption of Iranian intelligence computer systems used to control missile and rocket launches.
The U.S. president has been criticized in Washington by some in his own party as well as Democratic Party foes for ordering a retaliatory airstrike and then calling it off. Hawks in his own party fear the about-turn makes him look like a "paper tiger;" Democrats says it demonstrates confusion and "strategic incoherence."
But Trump's restraint appears to have calmed British fears of the president being reckless, with some officials saying it demonstrates his determination to calibrate his responses. Trump has said he wants to force the Iranians to return to negotiations in order to hammer out a better and more sustainable nuclear deal, in which the Iranians agree to curtail expansionist activity in the region.
"We certainly don't want to give the Iranians any encouragement or make them think that their threats or aggression will drive a wedge between us and Washington," a senior British diplomat told VOA.
"Tehran is calculating that it can use brinkmanship to isolate Trump and to get the Europeans en masse on side against Washington, hoping to weaken the American sanctions regime. We need to set them straight. One can dispute whether the U.S. should have withdrawn from the nuclear treaty in the first place, but we are where are," he added.
The change in Britain's tone appears to have been noted in Tehran. On Sunday, officials there said they were disappointed in the talks they held with a junior British foreign minister, Andrew Murrison, describing the discussions as "disappointing and repetitive."
Speaking in the Iranian capital, Murrison said Iran "almost certainly bears responsibility for" the mining, but added, "I was clear that the UK will continue to play its full part alongside international partners to find diplomatic solutions to reduce the current tensions."
Britain also signed on to a joint statement Monday with the U.S., Saudi Arabia and the United Arab Emirates expressing "their concern over escalating tensions in the region and the dangers posed by Iranian destabilizing activity to peace and security both in Yemen and the broader region."