The landscape of the eastern Syrian desert is so flat that from a vantage point 300 yards away you can almost see the entirety of Islamic State’s minuscule last pocket of territory.

Women in black abayas walk the street that runs through the village of Baghuz in Deir Ezzor province – a hamlet so small it does not even feature on the map – while white Toyota pickups speed past.

Once-vast, cross-border territory that had covered the size of Britain has been reduced to just a square-mile patch, surrounded on the eastern side by the UK-allied Syrian Democratic Forces (SDF) and cut off by the Euphrates river on the west.

The topography has made it easy for the SDF to keep an eye on its enemy, but…