Part of a letter in today's Guardian from Lord Avebury -

"My grandfather purchased Silbury Hill, introduced the first legislation to protect ancient monuments, and placed the hill under permanent guardianship. As owner of the site, I am concerned by the conflicting messages now being sent out by English Heritage, such as their plan to allow a "time capsule" to be buried in the monument. The current Silbury Hill conservation project, for which EH deserves credit, is designed to restore the original fabric by backfilling with pure chalk. Placing a foreign object in the monument offends conservation principles, as well as the spiritual beliefs of some people."

http://www.guardian.co.uk/letters/story/0,,2129468,00.html