Nothing on that balmy August evening seemed even slightly out of the ordinary. Peggy Hodgson was busily tidying up her terrace house in Enfield, North London, after her four boisterous children had once again left it looking like a pigsty.
Mrs Hodgson’s daughters were upstairs getting ready for bed. As usual, 11-year old Janet was playfighting with her elder sister, Margaret.
Then, as the pair rolled around and giggled on the bed, something most peculiar happened: a chest of drawers began sliding slowly across the floor towards them.
The two sisters watched aghast as the chest shuffled across the room as if dragged by a pair of powerful but invisible hands. They were even more afraid when they realised that the piece of oak furniture was about to block their bedroom door - their only means of escape.
Luckily for the children, their mother burst into the room to complain about the noise.
She grabbed the chest and shoved it back against the wall. But the invisible force continued. Peggy watched in terror as the chest once again began sliding across the room.
This time, the piece of furniture moved far quicker and Peggy could do nothing to stop it.
She tried again to shove the chest back against the wall but failed. And this time she could feel an inhumanly strong force in the room.
Objects would miraculously appear and disappear before the eyes of terrified onlookers.
Confused and terrified at what she was witnessing, Peggy gathered up her children and fled the bedroom in panic. And thus began one of the strangest cases of alleged haunting ever recorded in Britain.
Over the following months the so-called “Enfield Poltergeist” turned the lives of the Hodgson family upside down. Toys, plates, cutlery, books and pictures would all inexplicably fly across the room.
Such encounters may sound utterly absurd. But what makes the Enfield case so remarkable is that the events were exhaustively investigated by respected academic researchers and - more pertinently - were witnessed by more than 30 independent witnesses, including police officers.
Although the haunting happened 30 years ago, Janet and Margaret have not spoken publicly about it since childhood. They are still wary about discussing the incident in depth, as their lives have moved on.
Desperate for an explanation about what could be taking place in their home, the family turned to the Society for Psychical Research, a respected scientific body that examines cases of alleged haunting from an academic perspective.
It sent two investigators, Guy Lyon Playfair and Maurice Grosse, to examine the evidence. And to avert any claims of trickery, the society drafted in an independent barrister, Mary Rose Barrington, to doublecheck all of their work.
This would ensure that there could be no credible claims that the pair were being anything other than meticulous, honest and impartial in their investigations.
Sure enough, over the following 14 months they spent on the case, the two researchers catalogued a range of inexplicable phenomena.
Boxes flew across rooms, ornaments floated in mid-air, books mysteriously appeared and disappeared. Strange knocking sounds were heard inside walls.
It was all very peculiar. But there was worse to come. One morning when Guy Playfair was working at the house, he heard a “tremendous vibrating noise”.
"I really thought someone was drilling a great big hole in the wall of the house," he says. "I tore into the bedroom and there was quite a commotion. The whole fireplace had been ripped out.
"It was one of those old Victorian cast-iron fires that must have weighed at least 60lb. It was so heavy even I couldn’t pick it up.
"The children couldn’t have possibly ripped it out of the wall. It just wasn’t possible. We caught the incident on audio tape, including the fireplace being ripped out of the wall."
Events were soon to take an even more disturbing course. Late one evening, when the children were asleep in their rooms and Maurice Grosse was downstairs compiling his day’s findings, he was disturbed by the sound of Janet screaming.
Maurice ran to the foot of the stairs only to see the 12-year-old apparently being dragged through her bedroom door by an unseen force. Janet was then hauled down the stairs and dumped unceremoniously at Maurice’s feet.
This incident was also caught on tape and was just the first of several incidents in which the poltergeist apparently picked up Janet and tried to carry her off.
Soon afterwards Janet was even seen floating in mid-air - and this time there were two independent witnesses. A lollipop lady and a passing baker both glanced up at the house and through a top-floor window saw Janet apparently hovering above her bed.
And that wasn’t all. Apparently in the grip of some disturbed force, Janet began swearing and hurling insults at those in the room in a disembodied voice quite unlike her own. So was this proof of a poltergeist, or simply a child playing pranks?
The investigators began interrogating “the spirit” - and the answers they got were decidedly sinister.
The poltergeist identified itself as a man named Bill, who explained that “I had a haemorrhage and then I fell asleep and I died in a chair in the corner downstairs.”
What could this mean? Astonishingly, subsequent research showed that long before the Hodgsons had moved in to the house, an old man called Bill Wilkins had indeed lived there. And he had died of a brain haemorrhage while sitting in a living room chair.