Evil is out there, and if we call it, it will come, says Tom Willis. Stephen Lewis speaks to the exorcist whose fight against the forces of darkness reaches the nation's TV screens tonight.

When an ancient burial site was discovered in the East Yorkshire village of Wetwang, retired East Riding parish priest Tom Willis believed something more may have been disturbed than the human bones it contained. An evil presence could have been unleashed too.

Mandy Palmer and her daughter Rosebud had been perfectly happy in their bungalow in the village until the burial site was unearthed, says the white-haired clergyman. But suddenly, their home was possessed by what Mandy describes as a 'terrible sense of evil.'

It was an evil that seemed to affect their beloved pets most - at least at first. Their finch lost its feathers, and stopped singing or flying. Their dog went blind, and a parakeet died of what Mandy believes may have been fright.

Belongings disappeared, strange accidents occurred, and Mandy and Rosebud were both sick.

Then, in the most terrifying incident, Rosebud was stabbed in the leg by a pair of kitchen scissors which seemed to have found a life of their own.

That was when Mandy called in Tom Willis.

As well as being a former Bridlington vicar who has dedicated more than 40 years to his parishioners in various parts of the East Riding, he is also an exorcist - one of 12 clergymen in the York diocese alone who have dedicated their lives to the 'ministry of deliverance'.

He believes that since the repeal of the Witchcraft Act in 1951, there has been an explosion of demonic possessions and hauntings in the UK, with vicars and priests being increasingly called upon to cast out the devil in the name of God. It may, he believes, have something to do with the way people are increasingly dabbling with the occult.

"I certainly believe that evil exists and that it does have intelligence," says Mr Willis, now 71 and living in Beverley. The casting out of demons has been part of the church's ministry for 200 years, he points out - and Jesus himself talked about the devil existing, as part of God's creation. The evil is not stronger than God and normally we are protected from it, he says.

"But if people call it, it will come."

He had no doubt that the 'evil presence' Mandy complained of was very real. And when he went to the Palmers' home to drive it out, he allowed the TV cameras to follow him.

The result can be seen in an Everyman documentary - The Exorcist - to be screened tonight on BBC2 at 9pm.

The feeling of evil in the bungalow, Mandy tells the programme, was almost palpable.

"You could feel a cold patch of air when the evil spirit was around," she says. At one point, chillingly, she adds: "It's already got a taste for killing - it's made up its mind to kill."

Tom Willis, however - a veteran of many exorcisms - wasn't going to let an unseen spirit spook him. He admits he can never actually see or sense the spirits he exorcises.

The most he experiences, he says, is 'a kind of shiver or a zig-zagging feeling around my eyes.'

That was what he felt when he went into the Palmers' loft. But he wasn't frightened by whatever it was that was there. Exorcists, he jokes, are a little like doctors - too involved in what they are doing to be aware of how unpleasant or frightening it could seem to someone else.

Not so the TV cameraman. The crew heard some banging up in the Palmers' loft. "It frightened the cameraman a bit," says Mr Willis.

The exorcism itself was fairly routine. "We simply went around one night, prayed in the house, prayed that the evil might depart," he says matter-of-factly.

"I blessed each room with holy water, made holy water crosses on each of the walls, and commanded the evil to depart. It seemed to do so."

Mandy and Rosebud have since moved to Scotland: but not because their former home is still haunted. "They didn't want to sell it before they knew it was at peace," says Mr Willis.

Exorcisms aren't always so easy, however. There are a number of reasons people may call on an exorcist, adds Mr Willis.

Apparitions that keep appearing out of nowhere; doors that bang closed for no reason; rooms that suddenly get icy cold; objects moving about apparently of their own accord - or else, as in Mandy and Rosebud's case, an evil presence that manifests itself as an 'overpowering sense of menace or threat'.

Dabblers in the occult, who get more than they bargained for when using the ouija board or holding a seance, also sometimes call on the exorcist's services.

There are also 'good' visitations such as the case of the mother of a young baby who woke in the middle of the night to find the child's dead grandmother watching over the infant - though he's not sure in his own mind whether that's simply a case of wish fulfilment.

Nevertheless, evil is not just an idea in someone's head - it is very real, warns Mr Willis.

Among the more extreme cases he's had to deal with was a house in Hull where blood was running down the walls. He admits that was 'scary'.

Then there was the Hull policeman whose home he was called to in the middle of the night.

It was about 20 years ago. "The family called me out because the sitting room had been wrecked while they were upstairs," he says.

"A lot of things had been smashed.

"When I got there, the father and daughter were the least frightened. I got them to make a cup of tea, and I sat down with the son and mother, who were shaking with fear.

"I was sitting with my elbows on my knees when suddenly a bolt of electricity went through me and through them. It hit me first, I crumpled and saw the boy crumple a moment later, then the mother make an 'oomph! sound.

"It seemed to hit me with the most force. I was told later I had shrivelled before their eyes."

Even worse was the time he was called out to a party by a group of teenagers, one of whom was complaining of feeling weird. "One of the lads said he felt as if he was in a tiny bit of his body and something had taken him over," says Mr Willis.

Then he noticed another young man, a 19-year-old, also acting strangely, stroking himself and 'going into himself'. "I said: 'Are you all right?' and he said 'no'" explains Mr Willis.

He approached the teenager to lay hands upon him. "And he snarled at me like a rottweiler. I thought he was going to bite me, or attack me.

"But then I remembered the books say it doesn't attack you, so I hoped the books were right!"

Everyman: The Exorcist, BBC2 tonight, 9pm.

Updated: 10:33 Wednesday, January 16, 2002