Today marks 31 years since the brutal murder of a schoolgirl sparked the biggest investigation in Kent Police's history.

Claire Tiltman was stabbed in a frenzied attack down an alleyway off London Road, Greenhithe, on January 18, 1993. She was just 16-years-old.

The Dartford Grammar School for Girls student had left her home in Woodward Terrace, Stone, at about 6pm to walk less than a mile to a friend's house in Riverview Road, Greenhithe.

But just half an hour later, Claire – who was affectionately nicknamed 'Tilts' – was attacked after she took a detour to buy cigarettes before walking back down the A226 London Road.

She suffered nine stab wounds before she escaped her attacker.

The teenager later collapsed and died on the pavement despite attempts by passers-by to save her life.

The brutal and motiveless murder shocked the county and the nation.

Following the attack police issued an appeal for witness, offered a £1,000 reward for help in finding her killer and Claire's face was on the front page of the local newspapers.

More than 1,500 statements were taken and 40,000 documents reviewed.

But despite officer's efforts and massive publicity, the case – named Operation Artist – remained unsolved for more than two decades.

Claire had celebrated her 16th birthday just four days earlier and was the only child of Cliff and Linda Tiltman who both passed away before her killer was brought to justice.

At the time of her death she was completing her bronze Duke of Edinburgh award at Dartford fire station and harboured dreams of becoming a firefighter.

Her friends never gave up hope and campaigned tirelessly, holding a candlelit walk on the 20th anniversary of her death to re-trace her last steps and re-ignite a public appeal for information.

They asked for as many people to take part and to bring a candle or torch as they walked from The Bull pub in London Road to a service at St Mary's Church, Greenhithe.

In the House of Commons, then Prime Minster David Cameron also joined the appeal for information and said the government would do "everything it can" to support the police investigation.

Then, a year later, there was a breakthrough.

Former milkman Colin Ash-Smith was charged with Claire's murder in February 2014 – 21 years after the "frenzied, rapid and brazen" attack.

He was first questioned as a suspect after he was arrested for a knife attack on healthcare assistant Charlotte Barnard, 21, in October 1995, less than 400m from where Claire was stabbed.

But at the time there was no evidence to link him to her murder.

Following a cold case review and a change in the law which allowed jurors to hear a defendant's bad character, including previous convictions and behaviour, he was charged.

This meant the jury could hear the details of the 1995 stabbing and an incident seven years earlier where a 27-year-old woman was left for dead in a Swanscombe quarry.

The changes were said to be two of the crucial factors which led to his conviction.

A five-week trial began in November 2014 at Inner London Crown Court and in the December the jury convicted Ash-Smith unanimously.

He was 24 at the time of the attack and living with his parents, former Labour councillors Diane and Aubrey Ash-Smith, in Milton Street, Swanscombe.

During the trial, the court heard the murder was carried out by a "ruthless, predatory, armed killer" and it "was a killing for the sake of killing".

Several witnesses claimed to have seen a man in a light-coloured, waist-length jacket walking down London Road at the time.

Ash-Smith was known to have worn a similar jacket and had it on at Claire's funeral just a few weeks later.

The court also heard he boasted about being dubbed the 'Swanscombe Psycho' and had confessed to Claire's murder while in HMP Wakefield between 2001 and 2003.

He was said to have told convicted sex offender Stefan Dubois he had seen someone on a zebra crossing and then "snapped and attacked".

The court also heard Ash-Smith phoned the police incident room the day after Claire's murder because he feared either he or his car had been spotted that night.

He then created a fake alibi when questioned by police six days later, claiming he had driven his mum to see a constituent before they returned home by 6pm.

Ash-Smith gave evidence in court saying he had a collection of 20 to 30 knives, had written "assault plans", stalked a woman and broken into another's home with a plan to sexually assault her.

The court also heard he had once wrote he would "kill a schoolgirl" because he claimed it sounded "impressive".

Ash-Smith had already spent 19 years in jail for two other near-fatal attacks on women but denied murdering Claire.

He was found guilty and sentenced to serve a minimum of 21 years behind bars before being considered for parole.

The judge had to sentence according to the law in 1993.

But if he had committed the murder after a change in law in 2003, the minimum term would have been 30 years.

A year later, in December 2015, Ash-Smith was refused leave to appeal his conviction meaning he may never leave prison.

Over the years, documentaries have been made about the murder investigation which was the biggest Kent Police had ever overseen.

It featured in a three-part BBC4 documentary The Prosecutors and as an episode in documentary series Murdertown.

They looked at how police and legal teams built a case against Ash-Smith and the impact Claire's death had on the community.

In April 2016, Dartford council approved the re-naming of Fastrack Manor Way to Tiltman Avenue after councillors and her family backed a campaign to have it changed.

Stone Parish Council has paid tribute to Claire today and are planting Claire Roses at the centre to mark 30 years since she died.

In 2022, a new eco-centre was opened in Cotton Lane, Stone, dedicated to Claire by the parish council after consulting with her family and friends.

The building is used for a variety of environmentally-friendly and educational activities for young people including scouting.

Speaking at the opening, friend Emma Edwards said it was great to see something "really positive" associated with Claire's memory.

"Obviously there is a lot of pain associated and linked back to how Claire left us," she said.

"But seeing something like this which is going to have young people doing their Duke of Edinburgh that will come here, which is what Claire was doing when she left us, and seeing the difference this is going to make to young people that live in the area is really amazing.

"I hope they will have lots of fun and maybe be a bit mischievous exactly like Claire used to be."