A parish priest plans to exorcise the house where quadruple killer Mark Hobson twin sisters Claire and Diane Sanderson, to rid the village of an "evil cloud".

But what is an exorcism? Will it work? STEPHEN LEWIS speaks to two Yorkshire exorcists to find out.

The "quarter house" in Millfield Drive, Camblesforth, doesn't look anything special from the outside.

If it were not for the awful events that happened there last year, there would not be anything to mark it out from other homes in the street.

This particular house, however, hides a dreadful history. It was here, just over a year ago, that the bodies of twin sisters Claire and Diane Sanderson were discovered. They had been murdered by crazed killer Mark Hobson - the man who went on to kill twice more before being apprehended by police in one of North Yorkshire's biggest murder hunts.

Not surprisingly, the house where the girls' bodies were found is now called the 'house of horrors' by national tabloid newspapers. And not surprisingly, despite having been up for sale for nearly a year, no one has wanted to buy it.

Now parish priest Jonas Mdumulla, the Church of England vicar for Camblesforth, Drax and Carlton, is proposing to exorcise the house, to drive out the evil elements it contains and lift the "evil cloud" hanging over the village.

Any mention of exorcism prompts memories of lurid 1970s horror film The Exorcist, starring Linda Blair as a little girl possessed by the devil. Images of black-clad Roman Catholic priests holding crucifixes and carrying bottles of holy water also spring to mind.

Retired North Yorkshire vicar Graham Taylor - the man who has recently found international fame as Shadowmancer author GP Taylor - admits that in some ways, the 1973 film gave the practice of exorcism a bad name.

But actually, he says, it is a practice that has been around for a long time, and is a perfectly reputable part of a priest's work. "In fact, it used to be an offence for a priest to be unable to cast out an evil spirit," says the former vicar of Cloughton.

There is nothing illogical about a priest believing in the existence of evil spirits, he points out.

"It reaffirms that there is actually a spiritual dimension to life."

Graham says he has performed a number of exorcisms - during which at least once he found himself in the presence of "something which was extraordinarily evil."

He had been called in to exorcise a "presence" from a flat in Whitby which was on the site of an old hospital. "I could feel there was a presence there which was terribly evil and I was actually quite scared," he says. "There was this intense cold in one part of the room. But once it was prayed for, it went. You could feel it change, and there was no cold there any more."

Most exorcisms, says Graham, are relatively straightforward. What the exorcist is doing is commanding an evil spirit to "depart to the place God has prepared for it", there to await judgement.

"It is a question of going into a house and praying that whatever evil spirit is there is banished from that place and that the void is filled with God's holy spirit," Graham says. "It is like emptying the slops out of a teacup and filling it with fresh water."

That doesn't mean it is something to be taken lightly, however. Before attempting an exorcism - in which the walls and doors of an affected house will often be sprinkled with holy water - a priest has to prepare him - or herself mentally and physically, says Graham.

In his case, that involves fasting, to reach a state spiritual attunement, and then a confession of his sins so as to be "in a state of grace with God." That gives him the strength and courage to confront whatever evil may be awaiting him. "Knowing that God is within me, I know that the power within me is greater than any other power."

In the case of the house at Camblesforth, he says, it is possible that the dreadful act carried out there has left a negative energy that is perceived to this day by anyone who visits. Such a negative energy often occurs where an act of incalculable evil has been committed, he says.

"I don't think it has got any intelligence of its own. It is something we can transmit out of ourselves, and it remains within the house."

An exorcism may be just the thing, he believes - on a purely psychological level as much as a spiritual one, because it will give people the confidence that whatever evil was there has been driven out.

"I think it will definitely work," he says. "It will be like a spiritual spring clean, and nothing of darkness or evil will dwell in there again."

Tom Willis is a former East Riding vicar who is one of 12 Church of England clergymen in the York diocese who have dedicated their lives to the "ministry of deliverance" - a term the C of E prefers to "exorcist."

He believes the cloud hanging over the Camblesforth house may be the result of one of two things: Hobson's own guilt and horror at what he did, or his victims' anguish.

Not all presences or hauntings are necessarily evil, he says (see panel, far right) - they may simply be lost or desperate. His advice to the Rev Mdumulla is to find out as much as he can about what went on in the house before he attempts an exorcism, so he knows what he is dealing with.

If it is a dangerous or evil spirit, he would be well-advised to take other people with him when he enters the house.

Mr Willis, who says he has blessed or exorcised about 2,000 houses and buildings during the past 45 years, says he has never felt directly threatened by a spirit that he commanded to leave.

But a spirit did once try to take revenge on him through his wife, he says.

He had visited a house where a family claimed a doll had been possessed by an evil spirit.

As he was driving it out, his wife at home was simultaneously having a nightmare about a demonic doll possessed by a spirit.

"She woke up in a terrible state, and when I got home she said 'are we glad to see you!'" he says.

"I have no doubt it (the spirit) was trying to get revenge through my wife."

First identify the evil force

For Christians, there is the best of all precedents for believing in the efficacy of exorcism.

The New Testament (Luke, XI, 14-28) speaks of Christ himself casting out devils.

Every priest in theory is ordained as an exorcist, says retired East Riding priest Tom Willis, one of 12 clergymen in the diocese of York who act as exorcists. But what are the devils that need to be cast out?

Mr Willis has identified a number of different 'phenomena' which may require the attention of an exorcist - not all of them, by any means, evil. They include:

> Apparitions, which he believes are a kind of recording of some particularly vivid occurrence that happened in the past. He believes as many as one in ten people will see an apparition. He's never seen one himself. "But I've had a policeman shout out 'it's behind you!'" he says.

> Physical hauntings, in which objects move about, or there may be strange smells or sounds

> Poltergeists, in which living people exude an energy which causes things to happen. He has seen film of a man walking down a supermarket aisle, and all the tins flying off the shelves as they pass.

> Evil presences, which may be spirits in rebellion against God, he says. "They are not the Devil himself. He doesn't bother with us. We get the smaller stuff, the hangers-on."

> Evil or unfriendly presences which appear in response to occult practices such as sances. Often, these pretend to be friendly at first, he says - before showing their true colours by playing a malicious trick.

He remembers a group who had used a Ouija board to summon a spirit who claimed to have been involved at the Battle of Marston Moor.

"It gave them very accurate information for six weeks - and then suddenly it said one of them was going to die on Thursday. There was panic, but I said 'don't worry, it is just threatening you'."

Spirit of sad old lady

Mr Willis has been carrying out exorcisms for 45 years - and still remembers his first case, an example of an apparently frightening spirit that actually was not evil at all.

He was called to the home of a family in Hull where the wife feared she was having a nervous breakdown. She felt she was being followed around the house by an old woman, Mr Willis says - and whenever she went into the landing, became terribly depressed.

"One day her husband came home and found her crying. She said 'It's awful, your children leave you' and he said 'what are you talking about, they're only ten and 11.' She shook herself and said 'It wasn't me talking, it was the old lady'."

On investigation, said Mr Willis, it turned out there had previously been an old woman living in the house. She had lived with her son until he reached his 30s, when he married and moved to another part of the country. The lonely woman committed suicide by tying a rope round her neck, fixing it to the banisters, and jumping out of the window.

Her spirit was simply asking to be forgiven for committing suicide, Mr Willis says: and once he had blessed her and released her, the family's problems ended.

Updated: 11:05 Thursday, August 18, 2005