This is a mix between a poltergeist activity and a vampiric attack and not a lot of information is available on the internet. What I could collect from various books centers on the events that took place in 1938 in a family home from Thornton Heath (Surrey).
Suddenly objects started to be disturbed and the main victim of the incident was Mrs. Forbes, the mistress of the house. Items would be projected across the room, glass would be shattered and the smell of violets or rotting flesh would suddenly fill the air.
The activity escalated over time, until the terrified woman reported being visited by a vampire at night on 3 separate occasions over a couple of months. She described the vampire as a winged creature which bit her neck and drew blood.
As the media got a hold of the news and more and more people came for a piece of the action, dr. Nandor Fodor investigated the incidents and concluded that is was all made up by the victim as a way to relieve trauma caused by a childhood rape.