Psychic Diane Lazarus often helps her lawyer husband and police with murder trials. She tells Hannah Stephenson about speaking to the late Jill Dando and why she's not entirely sure Barry George was her killer.

Diane Lazarus loves sceptics. As a leading psychic she has met a lot, and all of them are willing her predictions and foresight into their lives to be wrong. You only have to Google her to see the non-believers challenging Diane's 'gift', as she calls it, questioning her psychic powers and the amount of help she has really given police in murder investigations. But the 42-year-old mother of two from west Wales, winner of last year's Psychic Challenge on Channel 5, is unfazed.

From childhood, Diane has been visited by her great great grandfather, whom she called the 'Lined Man' for many years, and her dead cousin Peter, gatekeepers to a world on the other side. "Spooky? That's my life," she says.

Since winning the Psychic Challenge, she has been inundated with offers from TV, radio and from people hoping to harness her psychic ability to find missing relatives, partners having a fling, or help solve crimes.

People from all walks of life, from judges to brain surgeons, visit Diane's office near her home in Cross Hands for a variety of reasons: it might be their career, a health or relationship issue, or to contact one of their dear departed. I ask her if she can tell me what item I purchased yesterday (it's a boat and I tell her it's a big item). She asks if it's a car, but then warns me that I've told her too much and her assumption has fogged the psychic visions. She doesn't guess again.

At regular readings, she will sit the client on her right side and face away from them, looking towards a blank wall opposite, where visions will appear to her.

"I don't like to look at people because you get into a situation where you assume. There's a fine line between your psychic ability and what you think. I hear voices in my head and my guides help me" (Her guides being her great great grandfather and dead cousin).

Diane doesn't eat beforehand because she doesn't want her blood to flow to her stomach, and the more water she drinks before the reading, the better the psychic flow.

She's had a flurry of electricians in and out of the house, which she puts down to pent-up energy. If she's angry about something, the lightbulbs often blow, she says. "If I don't work for a while I seem to build up a lot of energy. I break computers and microwaves. We've had no end of electricians in and out of the house, particularly if I'm in a mood."

The psychic readings, which can last several hours, leave her totally exhausted. She cannot say what percentage of her psychic observations are accurate, but says that feedback is positive.

She has, at the request of former police officers and criminologists, revisited the scenes of horrific crimes and told those concerned what happened. The dead victims often talk to her and take her on the route of their murder - frequently, she'll see the whole crime take place and feel the pain of the victim.

"I hate doing it and I really try to avoid it. I get hundreds of phone calls about missing people," she says.

She liaised with criminologist Bob Hinton to try to uncover new information on the murder of TV presenter Jill Dando, before the suspect was arrested, and went to the murder scene. "I stood across the road and focused on the house and as I did so Jill came back and hovered behind me.

"'He'd been watching me,' Jill said, 'for quite a while. I knew him. I'd seen his face'."

Diane claims that Jill told her he had a nearby flat which was full of newspapers and Diane had a vision of a man walking calmly away after the murder, to return later to his flat and stash the weapon.

She says now: "When Barry George was caught, he certainly seemed to fit my description of the killer and yet I'm still not quite convinced it was him. Neither's Bob."

One of the most recent cases she has worked on was that of Sandhurst officer cadet Blake Hartley who went missing more than two years ago.

"The family invited me out to Geneva, where the young lad had gone missing. He'd been murdered and put in a river. It was awful. I ended up traipsing through a river in the freezing cold and they found a thigh bone there and have the DNA. I know who did it but I'm afraid to say."

Married to solicitor Peter Lazarus, Diane sometimes assists him in his court work and has liaised with him in a number of murder trials.

"He's taken me to murder scenes and had me describe in front of QCs what happened in a murder case. I go to court for him quite often. When I see the person on the stand I'll ask him to ask a certain question and it often opens a can of worms."

Her visions are not always positive, she explains. She recalls one particularly upsetting case when she did a reading and healing session for a vibrant young mother - and saw a vision of her funeral.

"I saw a hearse submerged in flowers driving away from her house and dozens of weeping people. She was going to die. She had liver cancer and it had spread. That was horrendous. It really affected me. It was one of the worst experiences of my life. I wanted to snatch my hands off her shoulders and walk away. But I couldn't. I couldn't take away her hope.

"It's not always a blessing to have such a gift. It can be a curse at times. You don't always want to know things."

Diane has now written her autobiography, Mixed Blessings, which charts her spooky life and the psychic events which have surrounded her.

Mirrors mist up if something bad is going to happen, Diane says. Most recently her car rear-view mirror fogged over on the way home and she arrived home knowing that her dog had got under the cover of their swimming pool and drowned.

Diane believes that when you die, if you have behaved badly on this Earth you will pay your penance in the afterlife. When her violent father died, she saw his spirit at his funeral in Cardiff looking gaunt and miserable. The guilt comes back to haunt us, she believes.

"If we've lived good lives we join our old families and friends in a beautiful place. But if we have hurt people then the true knowledge of the effects of our behaviour hits us and we truly understand the pain we have caused."

There's another book on the cards, a TV project in Canada and a BBC documentary to come, yet Diane says if she had her time again she wouldn't want to be psychic, partly because she believes her life expectancy is reduced due to the energy she uses to do readings.

But she says she can switch her powers on and off.

"I don't go to the hairdresser's and watch spirits walking around, although I do get tested by people wherever I go to find out what I can do. It's as if everybody wants a message."

Mixed Blessings, by Diane Lazarus, (Century, £12.99).