"Over the centuries, various lunatics have riddled the ancient chalk construction with tunnels, mostly in an attempt to find treasure. The latest was in 1968 and was at, quite extraordinarily, the behest of the BBC. They hacked into this unique national treasure with impunity to make a series of gimmicky history programmes. They even built a recording studio in there... a huge series of corridors and chambers were excavated as part of that BBC project, in what can only be described as an act of archaeological vandalism."*

* http://www.dailymail.co.uk/pages/live/articles/news/news.html?in_article_id=491447&in_page_id=1770