Walk around any medium-sized town in Britain and you can usually find old city walls. Remnants of its medieval origins. My home city of Coventry has a few weathered sandstone relics like this. So does Milan, a place I visit quite often – walls, gates, defensive ramparts.

Centuries ago, keeping invaders out was a key concern – huge impenetrable walls helped. Modern warfare has changed all this. Now drones, airstrikes and long-range shelling mean walls are useless and the populations of encircled cities face death and destruction every moment. This, of course, is the grim reality for thousands of people in besieged towns and cities in Syria. What hasn’t changed that much though, is the way that besieging forces nearly always use starvation as a means of exerting maximum pressure on encircled populations.

In Syria it’s brought medieval suffering to thousands of people – including fighters, but overwhelmingly civilians – in places like eastern Aleppo city, the district of al-Waer in the city of Homs, the Damascus satellite city of Daraya, and the Yarmouk refugee camp area of Damascus. Yarmouk, you’ll remember, was the scene of that now-famous photograph showing a sea of people waiting for aid in a street of ruined five-storey buildings. More like something out of a CGI-enhanced disaster film than real life, the Associated Press photo temporarily thrust the issue of Syria’s sieges into the media spotlight. But that was in January 2014. Since then, war, the bombing and the sieges have ground remorselessly on.

In a recent report, Amnesty shows how “surrender or starve” tactics have become routine in Syria, with mass displacements of populations the inevitable end-result. Some of this has been at the hands of armed groups, though the majority is the work of government forces, usually operating in tandem with Russian air attacks and pro-government militia from Lebanon, Iran or Iraq. Dressed up as “reconciliation” deals or humanitarian “evacuations”, the reality has been very different. The endgame in numerous cases has been thousands of starved, bedraggled people carrying a few scant belongings, hastily bused out of cities while soldiers look on and in some cases even open fire on vehicles as a last act of cruelty. Apart from Yarmouk in 2014 and eastern Aleppo in December 2016, the sieges and their chaotic aftermaths have received very little media coverage. Which is unsurprising – a slow strangulation is much less dramatic than a sudden lethal blow. Here, for example, is how a teacher in an underground school in Daraya described the slow-motion impact of siege and starvation on his class of juniors: They had lost a lot of weight. There was this boy who was so sharp when I first met him as a five-year-old in 2014. By the time we were leaving in [August] 2016, he was unrecognisable. He was like a dead body with open eyes … He was no longer able to write although he used to be a very bright student. Hunger really took its toll on them. It was the hardest thing to see these little boys so skinny, so weak … It broke our hearts listening to their stories – one time one of the boys said he wished he would die like his father so he could finally get to eat in heaven … When we asked them to draw their favourite things, a seven-year-old boy split the page in two: on one side there were shops, fruits and vegetables; the other side was empty. The first was Damascus, the second was Daraya, he said.

Back in early 2014, I blogged about the sieges and starvation in Syria, likening them to something from a Primo Levi death camp memoir. Now, reading this Daraya schoolteacher’s despairing words, I’m reminded of innumerable similar episodes in Sergei Yarov’s book on the notorious Nazi siege of Leningrad during World War Two. People slowly losing all hope, beginning to bloat (a sign of impending death through malnutrition) and shedding their dignity and moral decency. In particular, during the harsh winter of 1941-42, the “Time of Death”, I found one scene described by Yarov particularly unforgettable. A person is visiting a relative’s apartment and suddenly, maddened by hunger, the visitor swoops down on the oilskin tablecloth and starts licking it for crumbs and traces of food. In Syria, we’ve already had years of besieged populations reduced to eating grass and nettles, cats and dogs. It’s been a slow-motion apocalypse. And neither city walls, modern international standards of civilised behaviour, or sophisticated means of communication and reporting, have preventing it from happening.