The attack on two oil tankers in the Gulf of Oman has escalated tensions between the US and Iran and raised fears of a surge in global energy prices.

Concerns over a spike in prices centre on Tehran’s potential to close the strait of Hormuz, the narrow shipping lane between Iran and Oman and the world’s most strategically important oil route.

Some ship owners have already taken matters into their own hands after Thursday’s oil tanker attack, the second in as many months, by barring their oil-laden vessels from moving through the strait.

The owners are seeking safety assurances, and are understood to be in talks to secure a naval escort for their cargoes through the waterway, through which almost a third of the world’s oil shipping passes.

One senior London-based ship broker said a number of tankers in the area are unwilling to move without these assurances.

“They are very concerned. Think of the volume of traffic which goes through the strait every day. A naval escort for each laden tanker would take time. Most charters are taking a step back to assess what measures could be taken,” he said.

Donald Trump played down fears Iran might close off the strait. The US president told Fox News on Friday that if it did happen “it’s not going to be closed for long”.

Paolo d’Amico, the chair of the tanker trade group Intertank, said the industry is extremely worried. “We need to remember that some 30% of the world’s crude oil passes through the strait. If the waters are becoming unsafe, the supply to the entire western world could be at risk,” he said.

Around 18 million barrels of oil are forecast to travel through the straits every day in 2020. This is more than half the 29.8 million barrels produced by members of the Opec oil cartel.

It is also a major avenue for Qatar’s liquefied natural gas (LNG) exports, or roughly 30% of the global LNG trade. UK gas supplies would not be affected by a short-term closure of the strait.

Timeline Recent tensions in the Gulf Show The UAE says four commercial ships off its eastern coast 'were subjected to sabotage operations'. Yemen's Houthi rebels launch a drone attack on Saudi Arabia, striking a major oil pipeline and taking it out of service. Saudi Arabia subsequently blames Iran for the attack. A rocket lands near the US embassy in the Iraqi capital, Baghdad, without harming anyone. It's not clear who is behind the attack, but after the initial reports, Donald Trump tweets: 'If Iran wants to fight, that will be the official end of Iran. Never threaten the United States again!' Saudi Arabia says 26 people were wounded in an attack by Yemen's Houthi rebels on an airport in the kingdom's south-western town of Abha. Two oil tankers near the strategic strait of Hormuz were reportedly attacked in an assault that left one ablaze and adrift. 44 sailors were evacuated from both vessels and the US navy assisted. Iran’s Revolutionary Guards say they have shot down what they called a US 'spy' drone they claim was flying in in the country’s airspace. The US military confirm one of its drones has been taken down, but say it was in international airspace. Donald Trump reportedly gives approval for the US military to launch strikes on Iran in retaliation for the loss of the drone, before pulling back at the last minute. The Iranian and US presidents trade insults, with Hassan Rouhani suggesting that Donald Trump suffered from a “mental disorder” and Trump once more threatening Iran with “obliteration”. Iran summons UK ambassador over an incident off Gibraltar as Royal Marines seize a tanker, Grace 1, the UK suspects of carrying oil to Syria. The International Atomic Energy Agency, the body tasked with verifying Iranian compliance with the terms of the nuclear deal, verifies that Tehran has breached the agreed 3.67% limit for enriched uranium. The UK government says three Iranian boats were warned off by the frigate HMS Montrose after Iranian boats 'attempted to impede' a British oil tanker in strait of Hormuz. Tehran denies involvement. In a major escalation, Iran seizes the Stena Impero, a British-flagged tanker, off its coast. Iranian officials later make it clear that the capture was in retaliation for the capture of the Iranian supertanker Grace 1 earlier in July. Despite US attempts in the courts to prevent it, Gibraltar says it will free oil tanker at centre of the Iran row. Iran gives assurances the oil is not destined for Syria, where selling it would breach international sanctions against Britain accuses Iran of breaching those assurances after Tehran acknowledged the oil had been sold, and the reflagged tanker Adrian Darya 1, previously known as Grace 1, had reached its final destination after the ship was photographed off the coast of Syria.

One London-based gas trader confirmed that no UK-bound tanks were en route through the straits at the time of the attack. Europe also has plenty of gas reserves after a mild winter, which should mean most of Qatar’s shipments will head east to buyers in Asia.

A long-term closure or restriction of traffic, however, would undoubtedly lead to higher gas prices and an economic boom for exporters in the US and Russia, he said.

The oil price climbed by a relatively modest 4% to $62.64 a barrel after the attacks in the Gulf of Oman, which is the gateway to the strait of Hormuz for inbound vessels, but experts say a prolonged hiatus could trigger record oil prices and reignite the risk of a global recession.

“We’re talking hundreds of dollars,” said Chris Midgley, the head of analytics at the oil market specialists S&P Global Platts.

“This would have a dramatic effect on the whole economy, right down to consumer spending. Every major recession we have seen has been preceded by a ramping up of global commodity prices … this would raise a huge recessionary risk,” he said.

Midgley said he expected diplomatic efforts to see off the risk of a complete closure, but that the world was nonetheless closer than it has ever been to an energy chokehold.

“In the days when the US had a huge dependence on energy from the Middle East it had a huge military presence in the area to ensure that the straits would remain open. What is different today is that the US has its energy independence. This is a significant change,” he said.

The US shale revolution means the former energy importer will become a net exporter of oil for the first time this year.

A global escalation in oil and gas prices could provide an economic boom for the country, but Trump is likely to weigh the benefit against the impact on consumer energy bills.

“The US still has a strong incentive to defuse the situation, and China – which relies heavily on energy imports - will also be motivated to step in,” Midgley said. “A shutdown of the straits would be the ultimate ‘nuclear’ option for Iran,.”