Jubilee Battery

This visit to Jubilee battery was to see if the tunnel we’d seen previously was now dry enough to take a look inside. This visit in early March (our previous visit was in May) was much easier, with less undergrowth. Still plenty of red ants though. On our first visit we could see the tunnel angled to the right for a short distance, before turning left to run perpendicular to the outside wall. This picture is taken from inside the tunnel looking back to the entrance. There are channels cut into both walls at a 45-degree angle – you can see one at the right of this picture, then there is another set nearer to the entrance. Q. What were the channels for? Were they to hold cables (there is another channel on one wall a little further in that looked as though it housed the electrical cables), or some sort of door fixings?