호르무즈 해협의 선박들을 위한 911 역할을 하는 영국의 소규모 기관

At a military base outside Portsmouth, England, a 24-hour service monitors the Persian Gulf, the Red Sea and part of the Indian Ocean, responding to distress calls.

When a ship comes under fire in the Strait of Hormuz, one of the first places its distress call is likely to be heard is thousands of miles away, on a military base outside Portsmouth, on the south coast of Britain.

“The most distressing events are ones where you are being called up by the crew or master of a vessel that has just been attacked,” said Commander Joanna Black, head of operations at the United Kingdom Maritime Trade Operations Centre.

The organization, led by the British navy, acts as a monitoring and emergency service for commercial shipping in the one of the world’s busiest maritime zones. It was founded more than 25 years ago, originally in Dubai, as part of the British response to the 9/11 terror attacks. It later switched its focus to helping to combat piracy off the coast of Somalia.

And since the start of the U.S.-Israeli war against Iran on Feb. 28, its services have become increasingly vital for sailors and shipping companies seeking to navigate the Red Sea, the Indian Ocean and the Persian Gulf — in particular, the Strait of Hormuz.

The agency’s evolution reflects the importance that Britain, an island nation highly dependent on international trade that once had the world’s most powerful navy, has long placed on maritime security and freedom of navigation. With its naval knowledge, the unit has the skills and technology to understand the challenges facing global shipping, and it has established itself as a trusted, impartial source of critical information.

When vessels report problems to the agency by satellite phone or email, it notifies local coast guard, military or other authorities best placed to assist. It also posts information about incidents and shipping traffic on its website and on social media, in the process becoming an invaluable source of information for shippers, policymakers and the public.

Sometimes “a vessel has been attacked by a missile or a U.A.V.,” said Commander Black, using the technical term for a drone, or “it can be that there is small-arms fire that is frequently directed at the bridge or the engine room.” For those involved it “can be absolutely terrifying,” she said.

Before the Iran war began, typical traffic through the strait was around 130 ships a day, according to the organization. But the number has fallen precipitously amid the conflict, to between eight and 10 a day now, the agency says.

The effective closure of the strategically important waterway has had a chilling effect on the global economy, driving energy prices higher. Around 850 large vessels remain stranded in the region, waiting until it is safe to pass through the strait, with around 20,000 seafarers affected.

Both the United States and Iran have sought to control the Strait of Hormuz. Iran says that only ships that have permission from the country’s Islamic Revolutionary Guards Corps will be allowed to pass, while the U.S. Navy says it is intercepting ships coming from or traveling to Iranian ports.

U.S. officials said in early March that Iran had used small boats to lay mines in the strait, and earlier this month, it said Iran could not locate all of its mines in the waterway. U.S. and European officials say the situation is complicated because no one knows how many mines have been laid.

Speaking on Monday in the control room, Commander Black said that the agency had so far received no reports from vessels of sightings of mines, although she added that very few commercial ships were plying the waters that may have been mined.

Concern about possible mines has been “enough to make industry incredibly cautious,” Commander Black said.

Since the start of March the organization has logged 41 incidents in the region, of which 26 were direct attacks on vessels resulting in a fire, flood or serious incident.

The vast majority occurred at the beginning of the war. Now, with a shaky cease-fire in place, incidents are more likely to involve vessels being hailed by radio and sometimes boarded, with seafarers being occasionally detained, Commander Black said.

Despite its links to the British navy, the organization prides itself on its neutrality and says that providing accurate, factual information is the basis of its credibility and value to shipping firms. The 18-person team at the center near Portsmouth, which is staffed 24 hours a day, gathers information from vessels no matter whose flags they fly or what sort of relationships their home countries have with London.

Cooperation with it is voluntary, but logging information with the organization can help shipping firms reduce their insurance costs. It works closely with a similar service operated by the French authorities in the Gulf of Guinea, west of Africa.

If a secondhand source informs them of an incident, operators in the control room near Portsmouth will first try to contact the crew of the affected vessel. If that proves impossible, they will attempt to talk with nearby ships to try to verify the situation.

“We have had instances where crews have ended up in the water, and by informing local coast guard they have been rescued or we can give them info about where people in the water were last seen,” said Commander Black. “It can get very busy in here, very tense — but you’ll find that when everything is happening, it’s quite quiet and focused.”

Stephen Castle is a London correspondent of The Times, writing widely about Britain, its politics and the country’s relationship with Europe.