A 10-strong team of ghost-busting experts has detected what they believe is paranormal activity at Plymouth's naval dockyard.
Researchers say they have "good" photographic evidence
The analysts spent two nights examining psychic activity in the dock's Hangman's Cell.
The Navy allowed the team in after numerous reports of strange sightings around Devonport Naval Base.
These include reports of a girl's ghost seen playing in the Master Ropemaker's House and a bearded sailor.
Since World War II, The Master Ropemaker's House has built a reputation as one of Plymouth's most haunted houses.
The Hangman's Cell, where 141 French prisoners-of-war were said to have been executed, contains what is believed to be the only remaining working gallows in Britain.
One of the team, Barbara Jones, from Abercynon, South Wales, said they finished their vigil at 0500 BST on Sunday.
She said the team of 10 all believed "beyond any degree of doubt" that they had detected paranormal activity at the base.
The hangman's cell was paranormally "very active," particularly below the hatch through which those hanged dropped.
There were changes in temperature in the cell, she said.
Although they did not see any ghosts, they had "very good" photographic evidence, yet to be analysed, which had them "jumping up and down."
Earlier, team leader Carole Bromley, known as Goldy, from West Drayton, Middlesex, said she had already seen a ghostly young girl and "quite a few
figures" on the base.
The paranormal researchers brought toys and blackboards for child ghosts to play with.
They also set up objects, including a made-up bed, balls, marbles and furniture in an attempt to detect poltergeists.
Their report is expected to be submitted to Commander Charles Crichton in the next few weeks.
Before the exercise, he said: "The people who walk here report spiritual activity to me all over the place - it's rampant."
Devonport is the largest naval base in western Europe.
It was founded in the 17th Century by William of Orange.