What is your brain up to while you sleep? Could it be working on a diagnosis? Since the days of Joseph and his many-coloured coat, people have wondered if dreams can predict the future. Now the psychotherapist Robin Royston claims that they can actually warn of health threats.

Dr Royston, who works in the NHS and for the Priory chain of clinics, is at the wild edge of dream therapy. He says that some dreams are disease alerts. “It’s like the dream knows something, but it’s a mystery how it can know. People want a nice simple explanation but there isn’t one,” he says. “We still don’t even know why we dream.”

Since he began researching in 1994, he says he has seen 400 examples of predictive dreams. One was from a man who dreamt of being attacked by two panthers. One panther dug its claw between his shoulder blades. The other loped off with a warning glance that left him deeply rattled.

“He discussed it with his counsellor because he thought it was about stress. But soon after, he found a mole between his shoulders that proved to be a malignant melanoma,” Dr Royston says. “The black panther seems a good metaphor for the mole: its colour, its danger. The second panther’s glance seemed a warning that he must check to see that the malignancy does not spread.”

Another patient dreamt that she was beating up a clone of herself and shouting “Bad Nancy”, Dr Royston says. “She was a French Canadian and after a while realised that mal Nancy sounds like malignancy.” She developed a cancerous lump that had to be removed.

Mere coincidence, surely? Not at all, says Dr Royston, who adds that dreams can warn you of scheming colleagues. “Dreams may pick up on factors you have not consciously noticed. If I started to feel threatened in dreams by someone I know, I would look at them closely; subconsciously I may have noticed they were giving suspect signals.”

Ian Wallace, an Edinburgh-based dream analyst and psychotherapist, also believes dreams hold crucial truths. “It all spills out during the night,” he says. He even uses dream-based therapy to help companies to work out their future strategies.

“When you dream you have no critical faculties,” says Wallace, who has worked on dreams for 25 years. “People’s dreams give you an idea about what will make them feel fulfilled and physically healthy.

“Sometimes themes aren’t obvious but often dreams speak in puns. Someone came to me who kept dreaming of going to Mull and Moldavia. We talked it through and it transpired that he had a problem he needed to mull over.”

OK, so what about my dreams? Most nights I spend either missing trains, being on the wrong train, or riding a motorbike with crucial components missing. Wallace barely pauses for breath: “Everything to do with transport is about your career and about your public image. Missing a train is about not wanting to be part of the herd but to be individual. It is not a lost opportunity, it is just that you’d rather have a different path.

“A motorbike is a very individual vehicle. The fact that it is broken indicates there is something there that you are not quite dealing with. It is frustrating for you.”

Freaky. I hadn’t spent five minutes on the phone to Wallace and he had his fingers so deep in my head he could have used my skull as a bowling ball. How do I learn more about my dreams? “The best way is to keep a dream diary, from which you can discern patterns and narratives unfolding,” Wallace says. “Every morning you should jot down the themes.”

As a parting shot, he advises: “Next time you are standing on that platform watching a departing train, imagine a gleaming intact motorbike on the platform beside you. Sit astride it, fire it up and go your own way.”

I can almost hear the first bars of Born to be Wild. Well, dream on.

DREAM READS

The Language of Dreams: A Visual Key to Dreams and Their Meanings, David Fontana, Duncan Baird Publishers, £4.99.