It happened in a séance room belonging to Leslie Flint, often regarded as one of the great British mediums who held up to ridicule and testing. Flint was known to contact both common people and celebrities in his time through an ectoplasmic "voice box", which would appear during mediumship, making the words come not from his own lips but the nearby air. On the 30th of August, a spirit came through in the presence of George Woods and Betty Greene. After much aloofness, it declared itself as Oscar Wilde.
The author spoke of his life and afterlife, and views of many differing topics for quite some time before fading away from "lack of energy". Given Flint's fame as a medium, audio recordings were taken of each session starting in 1955. The recording of "the spirit of Oscar Wilde" has survived and can still be listened to today. Many recordings can be found on this website. The full 30-minute recording of the Wilde séance is available online through this link. A partial excerpt and transcript is provided on "Oscar Wilde Returns". British videographer Jim Clark took an excerpt of the recording and jazzed it up slightly. Here is his computer animation of a photograph of Oscar speaking the words recorded almost 47 years ago: