Cold case detectives have launched a fresh bid to trace missing Norfolk teenager Steven Newing, saying the 40th anniversary of his disappearance could provide the final opportunity to uncover the truth.

Cold case detectives have launched a fresh bid to trace missing Norfolk boy Steven Newing, saying the 40th anniversary of his disappearance could provide the final opportunity to uncover the truth.

Officers say that even four decades after the initial inquiry, a single person could hold the key to the mystery. Det Insp Andy Guy admitted the case may hinge upon somebody with a guilty conscience finally coming clean.

Meanwhile Steven's mother, 74-year-old Jean Newing, told how the memory of her freckle faced 11-year-old, missing presumed dead from for 40 years tomorrow , continues to haunt her.

The mother-of-four added: 'I have never stopped thinking about him and this may be the last chance in my lifetime to find out what happened. I look at his picture and he is like my Peter Pan - the only one of my children who never grew old.'

Steven disappeared without a trace after leaving his home in Lee Warner Avenue, Fakenham, to visit a friend on the afternoon of September 2, 1969. This came five months after another high profile missing persons case - that of April Fabb - which also remains unsolved.

One theory was that both had been abducted but detectives were never able to prove this. Other leads, including the possibilities that he fell down a well or ran away from home, were also pursued to no avail. No body was ever found.

Mr Guy, who leads Norfolk police's cold case team, said: 'It is inconceivable that a young boy could disappear off the face of the earth without anyone knowing why.

'There is somebody out there who was either involved or who suspects they know who was involved. Maybe they didn't feel able to come forward at the time but, after all these years, feel the need to speak about it.

'These cases are never closed - we will keep the investigation going until we have an answer. But with the passage of time key witnesses or even the offender may have died or be in old age.

'The message is that, if you know something, this is your chance to get it off your conscience and to help Steven's family finally find out what happened to him.'

Over the years police have revisited numerous lines of inquiry, most recently eliminating the well theory by studying building foundations in the area he is believed to have last been.

Mrs Newing, who has since moved away from Norfolk, has given up all but the scantest hope that he is still alive but would like the case to be solved so that she can finally put his memory to rest.

'I've always thought that he had an accident and I suppose that I never wanted to believe that he was murdered,' she said.

'Obviously I have thought about what happened over the years and I still feel the pain. Nowadays I try to keep it at the back of my mind because you have to get on with life but it is hard, particularly when we have family celebrations and I imagine what he would be like if he was still here.

'But whatever theories I have heard have been mean nothing because you can't just continue to speculate. All I want is to find out the truth before I die.'

One key line of inquiry at the time of Steven's disappearance is that he was snatched by a paedophile. Shortly after he went missing there were reported sightings with a bearded man first at Sutton Bridge, Lincolnshire, then Kessingland, Suffolk. The sightings were never traced.

Police scoured old buildings, farms and outhouses. They made appeals on television and radio, locally and nationally.

Norfolk's cold case team has more than 30 investigations on its file and is systematically working through each one. Mr Guy said: 'These cases are always open but anniversaries provide a good opportunity to make a breakthrough.

'It may be that whoever is responsible will be thinking about what they did or it may jog the memory of somebody close to them.'

t Anyone with information should contact the cold case team on 01953 424548 or 0845 4564567.

The last Jean Newing saw of her 'mischievous son' Steven was him playing in the street with friends. It was a hot summery day and he seemed his normal care-free self.

He had just celebrated his 11th birthday and was due to start Fakenham Secondary Modern School a few days later.

Recalling that day in September, 1969, Mrs Newing said: 'I can't even remember my last words to him; I probably said something like 'make sure you're back by eight o'clock'. It didn't seem important at the time because I didn't think for one minute that I'd never see him again.'

Mrs Newing was not concerned when Steven failed to return to his home in Lee Warner Avenue, Fakenham, on time - she assumed he had been playing and lost track of time.

It was only after an hour that, with the disappearance of 13-year-old April Fabb from Metton, near Cromer, still fresh in her memory, she grew worried and contacted the police.

The subsequent police investigation saw officers scouring the countryside for any trace. They twice searched the family home to make certain Steven was not hiding or hidden there. Detectives are confident the family was not involved in his disappearance.

Despite potential sightings in Sutton Bridge, Lincolnshire, and Kessingland, Suffolk, no trace was ever found.

Mrs Newing said: 'Nowadays I think about him most when there is a big family event, like a wedding or a birthday.

'I can't help but imagine what he would be like now, what he would be doing for a living and whether he would be married with children.

'Losing one of your children is something you can never forget. He was the eldest so his brothers and sisters never really had a chance to get to know him.

'Nothing can bring him back but at least we can find out what happened to him. I would appeal to anyone who knows anything to put themselves in our position and think how they would feel if they lost someone they loved and never knew what happened.'

Steven was a freckle-faced boy with a distinctive and engaging smile. On the day he disappeared he was wearing a blue rollneck sweater with a yellow and green sweat over the top and blue jeans.

He had a birthmark across his bottom and carried the lasting scars of two childhood accidents: his elbow regularly came out of its joint and required hospital treatment following a fall and his teeth had been reset after he was kicked during a football match.

For years the most plausible theory seemed to be that Steven had fallen down an old well on the nearby Driftlands housing estate. This well was traced in 1979 but never excavated because of evidence it had been filled in a year before Steven's disappearance.

One ray of hope came in 1973 when Steven's father, Keith, believed he had spotted him on an Anglia TV broadcast about a pony sale in Watton. He was convinced Steven was part of a crowd featured in the programme.

He contacted the police who traced the boy and the two men who were standing near him to Outwell, near Wisbech. Although there was an uncanny resemblance, officers were able to establish that he was not Steven.