Passage: Despite the relatively shallow water in which she sank, the majority of bodies could not be recovered from Royal Oak. Marked by a buoy at 58°55′44″N 2°59′09″W, the wreck has been designated a war grave and all diving or other unauthorised forms of exploration are prohibited under the Protection of Military Remains Act 1986. In clear water conditions, the upturned hull can be seen reaching to within 5 m of the surface. The brass letters that formed Royal Oak's name were removed as a keepsake by a recreational diver in the 1970s. They were returned almost twenty years later, and are now displayed in the Scapa Flow visitor centre in Lyness. Royal Oak's loss is commemorated in an annual ceremony in which Royal Navy divers place the White Ensign underwater at her stern.A memorial at St Magnus Cathedral in nearby Kirkwall displays a plaque dedicated to those who lost their lives, beneath which a book of remembrance lists their names. This list of names was not released by the Government until 40 years after the sinking. Each week a page of the book is turned. The ship's bell was recovered in the 1970s and, after being restored, was added to the memorial in St Magnus. A number of bodies, including some that could not be identified, were interred at the naval cemetery in Lyness.

Question: Which act makes it an offence to interfere with a protected place?
Protection of Military Remains Act 1986