The Middle East has become a tinderbox where one small event could lead to a catastrophe on the scale of WWI, Jeremy Hunt warned on November 19 during his first visit to Iran as the UK’s foreign secretary.

Hunt used his time in Iran to try to persuade Tehran to back a UK-sponsored peace settlement in Yemen. He also urged the Iranians to stick with their commitment to the 2015 nuclear deal with the five major powers that remain signed up to it, despite Europe’s frustrating struggles in finding ways to get around the widely opposed US sanctions aimed at strangling the Islamic Republic’s economy.

Hunt spoke to the Guardian from the British embassy at which the three allied war leaders—Churchill, Stalin and Roosevelt—met 75 years ago to plot the victory over Nazi Germany. Explaining his “tinderbox” remarks, he reportedly said: “We have the issue of sanctions. There is the regional rivalry between Saudi and Iran that is getting more and more dangerous, leading to proxy wars. There is the need for recognition of Israel’s borders.

“Put this together, and what you have is the First World War risk–that any small event can trigger a chain of events with utterly catastrophic consequences.”

The foreign secretary made it clear that he was hoping that the UK was finally on the brink of a breakthrough to wind down the civil war in Yemen. The UK has tabled a UN resolution that allows for a cessation of hostilities leading to the start of peace talks in Stockholm at the end of this month.

He conceded that a meeting last week with the Saudi crown prince, Mohammed bin Salman, in Riyadh pressing the case for a UN ceasefire resolution had been “frank and difficult”, but insisted both sides had to make concessions to avert a humanitarian catastrophe.

The combination of war exhaustion in the fight against the Iran-backed Houthis in Yemen, the imminence of renewed famine in the war-torn country and the diplomatic disaster of a Saudi hit squad being exposed as behind the murder of the Washington Post journalist and Riyadh critic Jamal Khashoggi has conspired to put the Saudis on the back foot in Yemen, reported the UK daily.

“The truth is this wording of the UN resolution has challenges for Saudis because it is saying that it has got to agree to confidence-building measures, for example, money being paid to central government employees, a humanitarian evacuation of the wounded and not bombing any of the areas necessary for aid to get through,” Hunt said. “The Saudis see risks in this because Houthis have got a track record of exploiting things that have got a humanitarian label.”

Hunt stressed in the interview that Saudi Arabia, and not Iran, remained the UK’s strategic partner in the Middle East, but his faith in Riyadh was reportedly clearly shaken. He insisted a Saudi inquiry into those with ultimate responsibility for the actions of the hit squad might yet shape the future UK attitude to the country. But he stepped back from accusing the crown prince of masterminding the murder. “The Turks have said publicly they do not have a smoking gun, and I have not seen anything to contradict that view,” he said.