The test by researchers at Goldsmiths, University of London, tried to establish whether mediums could use psychic abilities to identify something about five unseen volunteers.

The results, carried out under test conditions, did not show evidence of any unexplained powers of insight.

But medium Patricia Putt said this experiment "doesn't prove a thing".

This Halloween challenge was an attempt to investigate whether professional mediums could demonstrate their psychic powers in a controlled setting - by inviting them to deduce something about people they had never met and could not see or hear.

The experiment, designed by Chris French, head of the Anomalistic Psychology Research Unit at Goldsmiths, asked two professional mediums to write something about five individuals who were concealed behind a screen.

These five volunteers were then asked to try to identify themselves from these psychic readings - with a success rate of only one in five.

This was a result that was "entirely consistent with the operation of chance alone", said Professor French.