A UAE-backed group has made significant gains in Yemen, in another conflict in which Abu Dhabi is on the opposite side to Riyadh. The Southern Transitional Council (STC) has in recent days taken full control of oil-rich Hadramout, and Al-Mahra bordering Oman, meaning the STC now controls all eight governorates that once formed South Yemen — and raises the possibility the south could declare independence once again. The capital Sanaa is in the hands of the Houthis, who control most other areas of the country.

The UAE and Saudi Arabia have supported different groups in Yemen for years, but the latest developments bring their rivalry there to a new level. The two Gulf powers have also backed opposing visions in Sudan’s civil war and they are rivals in the business arena too, competing strongly for inward investment and business deals.