The so-called “spectral stocktake” reveals a series of mysterious occurrences, many of which have prompted investigations by staff.
Some incidents are said to have led staff to resign. At one castle, employees have established protocols on how to deal with suspected sightings of ghosts or unexplained events.
Many of the events involve staff and visitors seeing mysterious figures, while others involve complaints that people were pinched or pushed, when there was nobody standing near them. Some reports involve items being moved around sites.
At Castle Rising, a 12th century keep in Norfolk, which was once the exile place of Queen Isabella, widow – and alleged murderess – of Edward II, “paranormal investigators” were called in by staff to conduct tests following sightings by visitors, many of whom claimed to have seen figures dressed in monks’ clothes.
Others said they had been pushed or nudged while looking around.
Norman Fahy, head custodian, said: “The most common phenomenon seems to be people getting pushed about. They seem to be prodded and poked. We seem to get these reports about once a week.”
Similar accounts of visitors complaining about being barged into, pinched or even slapped while there is apparently no-one around them have been made at Portland Castle, in Dorset, and Scarborough Castle, in Yorkshire, which, according to legend, is haunted by the ghost of Piers Gaveston, the favourite of Edward II.
Whilst popular ghost stories have previously been associated with some of the sites, this stocktake is thought to be the first time that staff at English Heritage, the government body charged with managing historic buildings, have been asked to log specific incidents reported by workers and visitors.
There have been so many sightings of mysterious figures in the labyrinth of tunnels below Dover Castle, in Kent, there staff there have created an established procedure for dealing with them.
Christine Pascall, the castle’s visitor operations manager, said: “About once a month we will have a report of something untoward, like a figure.
“We have a process that we put into place where we close down the system, evacuate visitors and a team of staff will sweep through the whole network of tunnels. It can be very frustrating for visitors.”
On one occasion, a group of schoolchildren were drawing in the tunnels. When they handed in their pieces of paper, one boy had written “Where is Helen?”
He told staff he had met a man in the tunnels dressed in a green jumper and brown trousers who was looking for a woman called Helen. A search was carried out but no such visitor was found.
On another occasion, visitors on a guided tour said a door had suddenly slammed shut and a stretcher trolley exhibit had moved very quickly along the corridor, as if pushed very violently.
Another site with a high number of reported hauntings is Battle Abbey, close to the site of the Battle of Hastings, in East Sussex.
Rosemary Nicolaou, visitor operations administrator at the site, said: “We tend to have sightings of monks, rather than soldiers.
"On one occasion, a school group which had just been round told me about an historical re-enactor they had seen, dressed in monks’ robes.
"But there was no such re-enactor on site. It couldn’t have been another visitor. I can’t really explain it.
“If I do hear of any sightings from visitors I will check out the details to see if there can be any rational, or practical explanation, because I am a sceptic, by nature. However, some of them don’t seem to have an easy explanation.”
The site with perhaps the widest variety of reports is Bolsover Castle, in Derbyshire. Staff and visitors have reported being pushed, seeing apparitions and items being moved around the site.
Some security guards have left their jobs after being spooked by seeing lights moving in parts of the property that were empty and hearing unexplained noises while on duty at night, according to Diane Hinchcliffe, the site supervisor.
On another occasion, she said, four builders working in the garden reported seeing a woman in a bustle-style dress who appeared to disappear though a wall. Two of the group declined to return the next day.
“Pretty much all the staff have had some experiences,” Ms Hinchcliffe said. “I am not necessarily a believer in ghosts.
"I think there is a rational explanation for everything, but there have been events that I cannot explain.”
Display figures have moved around the site at night, whilst items left in a locked storeroom, including visitors’ belongings, have also moved.
“Of course, I am always aware of the possibility of pranks and send ups,” she said.
"But there have been times when I have been the last to leave at night and the first to arrive in the morning and things have been changed. I have had things moved in locked rooms.”
Several visitors have reported seeing figures. One of the most commonly-sighted is said to be an apparition of a child, which is said to be seen holding the hands of young visitors.
At Portchester Castle, in Portsmouth Harbour, a member of staff heard the sound of horses’ hooves and then saw a riderless horse emerge from the walls of the castle, race across the area within the walls, and then disappear again.
A visitor also saw the incident.
At a medieval merchants’ house run by English Heritage in Southampton, staff raked over the gravel on the cellar floor before leaving work one evening and locking up.
The following morning, according to staff, footprints were clearly visible in the gravel, starting in the middle of the room and going into a wall. One footprint was partly in the wall.
Eltham Palace, in Greenwich, south east London, is said to be haunted by a former member of staff who died a week after retiring.
A man matching his description and with the same accent is said to have given a guided tour to visitors when the site was otherwise empty.