The first thing you notice is the smell. Sour and rancid, it cuts at the back of your throat; a powerful combination of rotting food, urine and sweat. Next it’s the flies, lots of them, circling in a frenzy. Then, out of the gloom, a pair of eyes emerges, and another – and then the shape of a young man, sleeping deeply on one of the grubby mattresses that line the floor of this derelict place. A few minutes from the centre of Calais, this is “Africa house”, so called because of the 40 or 50 Eritrean asylum seekers who now squat here, waiting and hoping.