Sorry every one but I'm going to have to debunk this site. Although this looks like a genuine souterrain in its construction It's alas not, and is actually fairly recent!.
Its location on the Western Plateau is right in the middle of the area excavated in the early 20th century, and it's not mentioned in the published excavation report, so it must date to about the late 1920's or early 1930's, possibly even later.
Its function: according to several archaeological collegues, a fox trap!, the unfortunate animal was apparently lured in at one end by some carrion placed at the other end, trapped by some wooden mechanism now gone and them dispatched in some way.
A rather macarbe function really!.
I hope this doesnt freak any one out who's been in it too much.

Adelphi.