When Milly Dowler was abducted on her way home from school in March 2002, the desperate and tragic search for the 13-year-old struck a chord with parents across Britain.

The last call she had made was to her father, to say she would be back in ten minutes or so at the family home, in the affluent commuter town of Walton-upon-Thames.

She never arrived, and despite millions of pounds spent on one of the highest profile police investigations in the past decade, no-one has ever been able to tell Bob and Sally Dowler what happened to their child.

In the weeks after she went missing, the Dowlers released touching, home videos of their daughter - ironing her jeans and playing the saxophone - that became etched on the national consciousness as the tragedy played itself out.

They said they could not rest “until the monster responsible for this ghastly crime is brought to justice and is behind bars”.

But thin evidence and a trickle of false leads inquiry had left detectives perplexed. There was no hard evidence – a lack of a forensic trail or a key witness who had seen the abduction.

The painful milestones of Milly’s 18th and 21st birthdays passed, and still, the family waited for answers.

In their last, anguished appeal, Mrs Dowler asked: “How can we find peace? How can we ever understand who could commit such an evil act and why? Imagine not knowing how your daughter died, or where or when and by whose hand, and imagine how we as a family live.”

Then, almost five years ago, for reasons that cannot be disclosed for legal reasons, a new suspect emerged: Levi Bellfield.

Police pieced together a mass of circumstantial evidence and it has taken years of slow and painstakingly casework to convince the Crown Prosecution Service to proceed with charges in this notorious case.

After a senior prosecution lawyer today announced that Bellfield will face trial over Milly’s murder, police could finally bring charges in the most notorious unsolved child murder of the past decade.

And the Dowlers, still at the same home which Milly failed to come home to eight years ago, could finally believe they may be closer to finding out the truth of what happened their daughter.

Amanda Dowler, known to all her friends as Milly, disappeared on March 21, 2002.

On the way home from school, still in uniform, she had caught the train from Weybridge to Walton, stopped at the station cafe to share a plate of chips with her friends, and then begun her ten-minute walk home to Station Avenue at 4.08pm.

When she had failed to appear by 7pm, Mr Dowler called police to report her missing.

Officers initially treated it as a missing persons inquiry rather than a possible abduction – a dilemma highlighted again years later by the slow Portuguese response to the disappearance of Madeleine McCann, which was also assumed to be innocent at first.

In the days that followed, the Dowlers made repeated multiple appeals for Milly to come home, including a reconstruction on Crimewatch.

The items she was carrying, which were never recovered, accentuated the picture of schoolgirl innocence. They included a Nokia 3210 mobile phone with “Milly” scrawled on it, a pencil case, a white plastic purse with a small red heart in the corner and a pendant with a fairy on it.

Surrey Police switchboards were inundated with thousands of calls after the appeals, but officers ended up “chasing shadows” during a series of false "sightings" from Ipswich to Scotland.

To add to the drama, the discovery of any bodies in Surrey was investigated and the Dowler family was told. In one such case, in April 2002, a female corpse found in the Thames, close to Walton, turned out to be that of an elderly woman.

Police devoted enormous resources to searching for Milly, looking at more than 350 sites, including dozens of waterways. They found nothing.

Officers carried out house-to-house inquiries – in the course of the entire investigation questioning over 2,800 people.

Levi Bellfield was at the time said to be living in a flat with his then girlfriend, Emma Mills, near to where Milly disappeared.

The address, in Collingwood Avenue, was visited ten times by police over two years. It was only on the 11th call that some new tenants answered, and police failed to track back to establish who was living there at the time Milly vanished.

Another potential clue was the local CCTV footage.

Images were taken from a camera at a Birds Eye Wall's premises opposite the bus stop where Milly disappeared. But within weeks Surrey Police had said that it had failed to help police with their investigation.

In fact, years later, a review of evidence uncovered a red car in one image which police believe may be central to the case. It belonged to Bellfield’s girlfriend and was allegedly often driven by the bouncer. It has not been traced since.

While everything suggested that Milly must have been abducted, it was a problematic theory to police because they could find no witnesses to a struggle outside the station involving a girl. Could it have been someone she knew?

As is usual in missing child cases, detectives had started by investigating Milly’s inner circle of family and friends.

For months, Mr Dowler, an IT consultant, was under surveillance because he was considered a viable suspect. His house, car and telephone was bugged by officers who believed he would lead them to her hiding place.

Every part of his private life was scrutinised. Officers checked the family computer and carried out exhaustive inquiries into his relationship with Milly.

He was eventually formally questioned over her disappearance, after which police accepted his account that he was at home when she was abducted.

Nor were there any clues in Milly’s past. She was plainly a well-balanced, intelligent and happy girl from a stable home. A study of her computer, her phone and her network of friends, disclosed no dark secrets that might have led her to run away - there was no internet chat room liaison, for example.

Police made three arrests after tip offs, but each one came to nothing.

By the summer of 2002, six months after she disappeared, police had told the Dowlers that they should prepare themselves for the worst: she was most likely to be dead.

The parents would not give up on Milly – and even continued to text message their daughter in the hope of a reply.

But the grim confirmation of her fate finally came on 18 September 2002, when her skeletal remains were discovered 30 miles from Walton, by mushroom pickers on Yateley Heath in Hampshire.

The discovery, far from providing a breakthrough in the inquiry, raised more questions than answers.

There was no DNA evidence from the corpse or surrounding area, no witnesses to it being buried.

Detectives seemed to have nowhere else to go – all leads were exhausted.

But then, five years ago, Bellfield’s alleged links to the area, his flat and the car, were pieced together.

A file was passed to the Crown Prosecution Service but it was deemed there was not enough evidence to prosecute.

A team led by Det Chf Insp Maria Woodall started again – questioning Bellfield’s associates, trying to trace the red car and pursuing every last line of inquiry until they uncovered what they believe to be fresh evidence. They put a new file to lawyers in August.

Police chiefs admitted it was a last throw of the dice in the quest for justice – and for eight long months they nervously awaited the decision, maintaining constant contact with the Dowlers.

Almost 3,000 days after Milly disappeared, they finally got the news they have been waiting for: there was enough evidence to go to trial.

Whether Bellfield was the man who abducted and murdered Milly Dowler is now for a jury to decide.