Three years ago, alarmed by the usurpation of political power in Yemen by a militia allied to Iran, a Saudi-led coalition launched a military campaign. The aim was clear: To uphold the legitimacy of the internationally recognised government of President Abd Rabbo Mansour Hadi, and check the advance of Al Houthis, Tehran’s proxies in the Arabian peninsula.

At a strategic level, the countries of the coalition, especially politically stable Gulf states with their sophisticated economies, simply cannot allow an armed militia on their doorsteps that answers to their regional adversary.

The conflict in Yemen has been gruelling, but the intent is as strong as ever. Inch by inch, up to 85 per cent of Yemeni territory has been wrested from the control of Al Houthis.

The Yemeni government announced the first major success of the operation in July of 2015, with the liberation of the key southern province of Aden. With the help of the coalition, by mid-August 2015 government forces had retaken five southern provinces. Another major success arrived in October that year, when the Bab Al Mandab Strait, one of the world’s busiest shipping routes, was liberated.

Yemen’s politics are complex, and volatile. For most of the duration of the war, Al Houthis were aligned with forces of ousted Yemeni president Ali Abdullah Saleh.

However, in December 2017, the underlying tensions that were a feature of this “alliance” came to the surface, and Saleh launched a brief insurgency against the Al Houthis in Sana’a.

True to form, the militia ambushed his convoy and murdered him in cold blood.

But Al Houthis must come to grips with the fact the coalition will not allow them to spread Iran’s agenda in the region. Saudi Foreign Minister Adel Al Jubeir was right when he said the war in Yemen was imposed on Saudi Arabia, and was not a war of choice. He also said the kingdom has been dealing with Iranian meddling in the region since the 1979 revolution. “Iran is the problem in the region, it is the source terror and extremism.”

Iran must be held accountable for supplying ballistic missiles to the militia.

For all their bravado, the Al Houthis must realise that they cannot win this war. A political solution that is acceptable to all parties is the only way out. What is not negotiable is the sovereignty of Yemen and the legitimacy of its recognised government.