Keith, who was extremely short-sighted, had broken his glasses the day before so his mum accompanied him most of the way and made sure he got across Stockport Road safely.

Had Keith been with his brother and sister as he normally was, or arrived a few minutes earlier or later or taken a slightly different route, he might never have got into the car. The driver was 21-year-old Myra Hindley and her passenger — who lived just round the corner from Keith’s nan — Ian Brady.

This is where Brady was brought from his cell in Ashworth maximum high security hospital on Merseyside in the 1980s after offering his ‘assistance’ to locate Keith.

He was playing mind games and had no intention of doing so. The landscape had changed, he said. He was confused. He couldn’t say where he had hidden Keith, after all.

But not far beneath where he once stood — and I am now standing — is a small patch of wasteland where suspected human remains have been found.

The site is in the vicinity of Shiny Brook, a stream which stretches for nearly a mile through the folds of rock and shifting layers of peat on Saddleworth.

Is the location significant? It would seem so.

It is within a few hundred yards of where three Moors Murders victims were buried: Pauline Reade, 16, John Kilbride, 12, and ten-year-old Lesley Ann Downey. Edward Evans, who was 17, was found bludgeoned to death with an axe inside Brady and Hindley’s home in Wardle Brook Avenue in Hyde, Manchester.

Keith, the bespectacled lad with the endearing grin, is the only victim who has never been found.

The depravity of the killing spree which claimed his life and those of four other children in similar circumstances, between 1963 and 1965, is still seen by many as the passing of a more innocent age.

Over the years, Greater Manchester Police have used geologists, geophysicists, archaeologists and anthropologists to help them look for Keith’s body.

At one point, a U.S. spy satellite was employed in the search and a cryptologist from GCHQ was drafted in to try to crack a possible code in letters shared between Brady and Hindley which might identify his whereabouts.

The terrain around Shiny Brook is probably the most intensely searched few square miles in Britain, perhaps anywhere.

But now a team of experts, including soil analysts and an archaeologist specialising in human remains — assembled by author Russell Edwards in his seven-year quest to find Keith — have discovered what they believe is the skull of a child aged around 12.

Samples of earth also revealed the presence of potential human tissue, calcium and other elements such as phosphorus and nickel which are indicators of human, not animal, remains.

The specimens have not yet been subjected to conclusive laboratory testing because the area is a potential crime scene. The police have been informed, however, and are preparing to exhume a small section of moorland. For the first time in 35 years, a blue tent, eerily familiar on such occasions, can be seen on the moor.

On a bright sunny day, with the heather in full bloom, Saddleworth, which straddles the metropolitan boroughs of Oldham in Greater Manchester and Kirklees in West Yorkshire in the shadow of the Pennines, is often described as breathtaking.

But, for many, a line from a poem by Rudyard Kipling, reproduced in a Manchester Evening News supplement about the Moors Murders, comes closer to the truth.

‘We meet in an evil land that is near to the gates of hell’ are the words printed at the introduction of the section entitled: ‘A Lonely Resting Place.’

He remembers how they bent the street light near their window so it almost came into the room.

‘We had the biggest light in Longsight,’ he recalled in his website (searchingforkeith.com). ‘The room was flooded with an orange glow every night.’

Keith tried to teach Alan, who was four years younger, to swim, which he excelled at.

In return, Alan helped Keith with reading, something he struggled with. ‘Keith had little time for anything but laughter and nature,’ Alan adds. ‘He was an ordinary, uncomplicated child, with his head in the clouds most of the time.

‘He lived for the natural world and animals and never returned home from a trip to the local park without a few finds — usually a handful of twigs.’

Until one day, on a short journey he had made a thousand times before, he simply vanished.

They didn’t have a telephone. Many working-class households didn’t in those days.

Brady, who had developed a burgeoning obsession with Nazi Germany, and Hindley, who had bleached her hair to emulate Aryan perfection, began their life sentences as the most notorious child killers in modern British criminal history, a description that probably still holds true today; ‘two sadistic killers of the utmost depravity, to quote the judge. Yet, for more than two decades, the Moors Murderers denied killing Pauline and Keith, only admitting their guilt in 1985.

They were taken to Saddleworth separately to help find the bodies. Pauline was found in 1987 but Keith never was and remained somewhere out there on Saddleworth. His mother made thousands of visits to that lonely place and wrote countless letters to Brady, begging him to tell where on the moor he had buried Keith. He ignored every one. ‘Ian Brady has tortured me for over 40 years and enjoyed every minute of it,’ she once said.

Hindley described the haunting last sight of Keith disappearing across the moor with Brady in correspondence with documentary maker and author Duncan Staff, who wrote Lost Boy, an acclaimed book about the Moors Murders. ‘I remember thinking then, as I later said to the police, that he looked like a little lamb being led to the slaughter.’