Please don't believe Most Haunted. Its all a sham - take a look at
http://www.badpsychics.co.uk for a long list of mistakes and errors made by the programme.
The best part is in the Most Haunted Exposed section - Derek got possessed by "Kreed Kafer". Thing is, Kreed was made up, and his name is an anagram of "Derek Faker"! Oh dear.