Russian and Syrian aircraft are pounding the rebel enclave of East Aleppo, which is besieged and isolated from the outside world. Some 250,000 to 275,000 civilians and 8,000 fighters are trapped there, with every likelihood that President Bashar al-Assad’s forces will go on attacking until they win or the rebels leave. Hospitals and care centres are being systematically destroyed. UN aid convoys are being denied access by government forces.