English Heritage has carried out a survey among its more than 1,800 staff to discover the country's spookiest sites, with Bolsover Castle in Derbyshire, England, the most spookiest.

Bolsover Castle was followed by Kenilworth, in Warwickshire, and Carisbrooke castles, Isle of Wight, said English Heritage, a charity that manages more than 400 castles, abbeys, historic houses and palaces.

The survey was carried out in the run up to Britain's spookiest festival, Halloween on October 31, famed for its "trick or treat" tradition, and the night when the spirits of the dead allegedly come back to life.

A spokesperson for English Heritage said: "Ahead of our Halloween and After Dark events program, we asked our 1,800 staff to vote for the spookiest site in our care."

"Our staff have intimate access to our historic places during its darkest hours. They are also immersed in the history of our sites and are aware of associated legends. In their responses, some staff members have also shared spooky tales and reported creepy goings-on including creaking doors, unexplained noises and moving objects," added the spokesperson.

Lucy Hutchings from English Heritage explained why Bolsover Castle was voted as the spookiest, saying "Bolsover Castle, the magnificent former home of William Cavendish, definitely has a dark side. Over the years, staff have reported time and again unexplained occurrences of objects moving, orbs of light, pinches and some have been told by visitors that they have seen William himself, wandering the lonely corridors."

Built on an ancient burial ground, Bolsover Castle in Derbyshire county, overlooks a town once described as "the Satanic capital of Britain."

As for Kenilworth Castle, a Medieval fortress voted as the second spookiest, it has been the source of spooky stories for hundreds of years. The castle was converted into a palace by Queen Elizabeth I's favorite suitor, Robert Dudley, in an attempt to woo her.

Staff have also reported many mysteries around the castle, including the so-called witness of "ghostly figures" and the hearing of strange sounds.

Carisbrooke Castle, on the Isle of Wight, is also riddled with stories of ghostly apparitions.