Since the disappearance of US resident and Washington Post columnist Jamal Khashoggi on 2 October, all eyes have been on Riyadh. Amid various reports of what may or may not have happened after he entered the Saudi consulate in Istanbul, international pressure has been mounting on Saudi Arabia to provide answers. But while the world is rightly outraged by this case, we must not overlook the country’s role in a tragedy playing out on a far greater scale: the war in Yemen, which the head of the UN has called the “world’s worst man-made disaster”.

The Saudi-led war in Yemen against Iran-backed Houthi rebels has had disastrous human consequences – and there’s no end in sight. Reports this week suggest Yemen could be facing the world’s worst famine in a 100 years, and over 75% of its population is in need of humanitarian aid or assistance. The UN Independent Group of Experts found that Saudi airstrikes in Yemen amounted to potential human rights abuses and breaches of international humanitarian law.

Since the coming to power of Mohammed bin Salman in 2016, Saudi Arabia has been pursuing a more hawkish foreign policy. This has predominantly centred around the perception of the threat posed by regional rival Iran, and attempts to curb its power and influence in the Middle East. This has resulted in the detainment of the Lebanese Prime Minister, Saad Hariri, and allegedly trying to force him to resign over concerns about Iran-backed political actor Hezbollah; attempting to isolate Qatar with the UAE, Kuwait, Qatar and Egypt because it maintained too close ties with Iran; and the going to war in Yemen to defeat Houthi rebels.

Saudi Arabia’s fear about Yemen is that the Houthis gain territory, potentially resulting in an Iran-backed grouping on Saudi Arabia’s doorstep. This is unacceptable to Riyadh.

Supported by the US and the UK in particular through arms sales, military training and intelligence (although the extent to which British and American personnel is involved in targeting decisions is not clear), the Saudis have carried out air strikes on civilian targets in Yemen. Whether or not this is deliberate has yet to be confirmed.

The consequences of the war, however, are very clear. The Yemeni economy has completely collapsed. Two million children are not in school, of which nearly half a million dropped out since Saudi Arabia became involved in the war in March 2015. More structurally, a highly fluid political picture is emerging, with alliances and rivalries constantly shifting as new political factions emerge, join forces with others, or split up. The presence of Al Qaeda in the Arabian Peninsula further complicates the situation.

There has been increasing domestic pressure in the UK from both MPs and activists for the UK to suspend arms sales to Saudi Arabia over its conduct in Yemen, or at least reconsider its relationship. As of yet, the UK government has maintained the belief that engaging with Saudi Arabia directly allows it to exert more leverage and influence over Riyadh’s foreign policy decisions, including in Yemen.

Yet a recent study by the Policy Institute at King’s College London, suggests that Saudi Arabia is able to exert more influence over the UK than vice versa, and that the UK is currently incurring damage to its international reputation as a result of its relationship with Saudi Arabia.

It may be that the disappearance of Jamal Khashoggi becomes a defining moment in UK-Saudi relations, in particular if the allegations are proven to be true.

But perhaps this defining moment should have come sooner. The devastation of Yemen by Saudi Arabia and its allies has been taking place for three and half years now, and with tens of thousands dead and millions displaced from their homes and at risk of starvation, maybe we are already long past the point at which the UK should have reconsidered its relationship with Saudi Arabia.

Armida van Rij is a Research Associate at the Policy Institute, King’s College London