ON a bleak winter's night, with the rain sheeting down and the wind blowing with bitter force, I arrive at Henry's sweet shop, on Hartlepool's Raby Road. It's unprepossessing, metal-shuttered and shrouded in darkness, yet from what I've been told, I know that it's far from ordinary.

Ever since they moved there about a year-and-a-half ago, John and Velda Donley have been aware of strange happenings. They bought what is now the sweet shop and flat above intending to live there while they renovated it. It was while they were carrying out the work that the phenomena began. "From day one of moving in there were a lot of strange noises but I put it down to something toppling over or noises from next door," says John, 42, a property developer.

"Then after about three or four months, I started seeing a tall man dressed very smartly in black with black, patent leather shoes. You always get a glimpse of him out of the corner of your eye and then he just disappears." Velda, 32, says that she too has seen the man several times.

The couple claim that their dog Henry, after whom the shop is named, often appears to sense a presence, following it with his eyes and sometimes cowering in a corner or leaping on them in fright. John says: "Whoever it is does not like dogs."

Chatting to John and Velda in their living room before the exorcism, they appear just like anyone else. They speak in simple terms, free of elaboration, and whatever the cause, their anxiety seems genuine.

John admits that at first, he doubted himself. "We've had electrical things like all the bulbs going and there've been times when we've been watching the telly and it's switched over to another channel - electrical things and noises you can always think of an excuse for. If I had just seen and heard things myself, I might have thought I was cracking up but because other people have seen and heard things, I think there has to be something in it," he says.

Yet disconcerting though all this was, the couple could just about live with it - until something more sinister happened. "I was decorating this room and out of the corner of my eye, I just caught a glimpse of a jet black shadow," says John. "The only way I can explain it is like in old films when the baddie had a flat black hat on and a black cape, and all I could see was his eyes." (He shields his face with his arm to demonstrate.) "What I felt was pure evil."

Initially, John and Velda sought help from a Catholic priest but were dissatisfied with his response. They were put in touch with Lana Grabinskis by a local fortune teller. "I don't think anyone wants to live somewhere where they know there's evil. I thought if we could get anyone to draw it out, then that's what we would do," says John.

When I arrived at the Donleys', Lana, 41, and medium Mike Reed, her exorcism partner for the evening, were already there.

My first introduction to York-based Mike was hearing him chatting effusively on his mobile phone. He then turned his attention to me, firing random words and questions while simultaneously talking to who I would later discover to be his spirit guide. I found this surreal and discomfiting - and unlikely to enhance his credibility - however, he did come up with the names Paul and Kathleen (my husband and grandmother's names). While some things seemed accurate, I felt uncomfortably like I was being manipulated.

Proceeding to the exorcism, Lana, from High Etherley, near Bishop Auckland, begins burning a potent mix of frankincense, myrrh and lavender oil. Alongside her is a bag of rune stones (symbols of protection) a crucifix and a vial of holy water. Calm and quietly spoken - in stark contrast to Mike - she explains how after starting as a psychic artist (drawing pictures of spirits) about ten years ago, she got into exorcisms by chance, when she visited the Wheatsheaf pub in Boldon, near Sunderland, last September.

"I did a drawing of a poltergeist and a little girl who was killed. The girls' toilets were the little girl's bedroom and we found bits of a dress and some hair, which scientists from the Centre For Life said was human hair," she says. Lana was asked to rid the place of its ghosts, which had been causing distress, and spent the next three weeks doing this.

Since then, she has performed a number of exorcisms in pubs and homes, using a medium to locate trapped souls and sending them on to the spirit world. "To me, it's all about people's fear. If I can ease that fear it's worth it, no matter how bizarre it might look," she says.

Accompanied by Mike, she takes her equipment to the main bedroom where for several moments, they conduct their work in privacy. At one point, Velda ventures upstairs but is turned away, being told that it's a crucial point: they have the evil spirit in the corner. Back in the living room, Velda sees a white flash in the television but neither John nor I witness it.

After the spirit has been banished, I'm allowed in to watch as Lana and Mike continue. Lana walks round the room, wafting smoke in every recess while Mike, deep in concentration, mutters prayers. When the process is complete, both lay a hand on the door and continue praying. They repeat this in every room of the house, working from the top down, with Lana sometimes making the sign of the cross with holy water. "The smoke helps purify a room. I've got to do every door and every recess to create a better balance of energies," she explains.

While Lana is working, Mike ventures an opinion as to the evil spirit's identity. "While we were doing the movement of the spirit, I felt as though he was an executioner. He feels that he has to atone for what he's done and over time, he's become more negative. It's like he's trapped himself in a corridor," he says.

When the exorcism is complete, Lana asks John and Velda to go upstairs and try to get a sense of the energy. While the main bedroom is fine, John feels uneasy in the spare room, describing the air as feeling heavy. Lana and Mike go in, shutting the door behind them. When they emerge, a short while later, it is with the news that they have sent a hitherto undetected spirit - that of a little girl - to the other realm. Lana explains that she and Mike held hands and felt the child - who Mike has identified as 'Molly' - pass between them. She says they summoned her mother, Eliza, from the spirit world to collect her.

It is only when Lana mentions first hearing the little girl when she was downstairs that something clicks. Without even thinking about it, I corroborate this, telling everyone that I heard her too. About an hour earlier, when I was in the living room with John and Velda, I remember hearing what sounded like a child laughing. Assuming it was from outside I asked: "What was that?" A second later, my mobile phone rang and I forgot about it. Now I realise that while the sound was clear to me, neither John nor Velda heard it.

The laughter may have been the product of my imagination, stimulated by the strange atmosphere and the power of suggestion. Yet as I leave the Donleys, hopeful that their spirits are finally laid to rest, I can't help but feel uneasy, as if in an understated way, I might have witnessed something truly inexplicable.

* To arrange an exorcism, contact Lana on 07944 310130. Starting in March, she can also be visited at a psychic fair at the Quality Hotel, Boldon, from 10am-5pm on the first Sunday of every month.