Aberfan

Tip number seven stood above the village on a hillside with springs running under it. The Coal Board had been told twice in writing that it was sitting on water and that a slide would come down on the school.

Heavy rain had filled it. At a quarter past nine on the Friday before half term, about a hundred and fifty thousand cubic metres of saturated spoil came down the mountain in five minutes and hit Pantglas Junior School and about twenty houses.

A hundred and forty-four were killed. A hundred and sixteen were children, most of them in one classroom, and five were their teachers. Nobody was brought out alive after eleven that morning.

The whole village dug. Miners came up from the pit and dug for their own children. The tribunal blamed the National Coal Board entirely and named nine men, and none was sacked or prosecuted.

The Board then took £150,000 from the disaster fund - money the public had given - to pay for removing the remaining tips. It was repaid in 1997.

The Queen did not go for eight days, and has said it was her greatest regret.