South Castle, or The Neck camp, is an Iron Age, or later prehistoric, promontory fort occupying a projecting headland on the south side of The Neck, which adjoins mainland Skomer Island (NPRN 402711) on the east side. The promontory is cut off by a 100m length of rampart, still standing some 3-4m high to the base of the ditch which flanks it on the outer (north) side. Beyond the ditch is a low counter scarp bank. The main gate is a simple gap towards the eastern end of the rampart. The gate gives access to a relatively level plateau inside the main rampart, with a natural or partly improved scarp slope lying some 30m inside the fort. The defences enclose a varied headland some 90m by 120m, enclosing 1.6 hectares, with the ground sloping off steeply on the west, south and east sides in sea cliffs. Two rectangular rock-cut platforms overlooking the sea cliffs from the south tip appear to be the only definite evidence of houses or structures within the fort. They are terraced into the slope on the uphill (north) sides, with coarse orthostatic walling completing the remainder of their circuit.

It is interesting to note that the main Skomer Island has no promontory forts, despite there being several usable headlands. It does however have dense evidence for hut groups and long-lived terraced fields of prehistoric date which The Neck lacks, save for some lightly-built boundaries and evidence for cultivation. Therefore, the siting of the promontory fort on The Neck, which was comparatively isolated from Skomer Island, is probably significant in terms of the fort's date or function.

Field visit by TGD and LB on 18th August 2010.

T. Driver, RCAHMW, 31st August 2010.