Armed rebels in Syria led by the Islamist group Hay’at Tahrir Al Sham (HTS) have taken a second key city, Hama, and were advancing last night on Homs. The surprise offensive began last week with the capture of Aleppo, Syria’s second-biggest city. HTS is proving to be much stronger and more advanced militarily than the Assad regime expected, after spending years investing in combat capabilities including special units and an entire drone force. Whether HTS can hold and expand the territories it has captured will depend on its ability to win the trust of the communities it now controls. In Aleppo, soldiers and police have already started defecting to HTS but it has a long way to go before it topples the regime. There were scenes of jubilation on the streets of Hama, as people ripped up posters of the president and toppled his statue. But there have also been traffic jams as his supporters flee south towards the capital. Damascus, is 100 miles from Homs and Assad’s Russian allies have launched an increasingly brutal bombing campaign on HTS-controlled targets.