The night before she died, a ten year old girl told her mother she had dreamt the school was gone. That something black had come down and covered it. The next morning, it did.

Her name was Eryl Mai Jones. She lived in Aberfan, a small mining village in the south of Wales, below a mountain of coal waste the colliery had been piling up for years. On the twentieth of October 1966, she woke and told her mother about the dream. There was no school there, she said. Something black had come down all over it. A few days earlier she had said something stranger still. She told her mother she was not afraid to die, that she would be with her friends Peter and June.

At a quarter past nine the next morning, the rain-soaked waste tip above Aberfan gave way. Half a million tons of black slurry slid down the mountain and buried Pantglas Junior School, on the last morning before the holidays, with the children at their desks. A hundred and forty four people died. A hundred and sixteen of them were children. Eryl Mai was one of them. She was buried, in a long row of small coffins, between her two friends. Peter, and June.

And here is the part that haunts this story. Eryl Mai was not the only one. In the days before, across Britain, strangers with no connection to Aberfan woke from dreams of a black mass, a suffocating darkness, a child in a Welsh valley. A psychiatrist named John Barker came to Aberfan and asked, through the newspapers, for anyone who had foreseen it. Seventy six people wrote to him. Many of their accounts had been told to someone else, and written down, before the slide. Barker was so shaken that he set up a bureau to collect premonitions, hoping to catch the next one in time.

It did not save him. Two of the bureau's own seers began to send in predictions of the death of John Barker himself. In the summer of 1968, at forty four, he died, suddenly. The files are still there. So is the question. Some of those people knew. We still do not know how.

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