A grief-stricken mum is imploring young people not to dabble in recreational drugs after a powerful painkiller caused the death of her 17-year-old son.

Kim Webster spoke out as an inquest into the tragedy was held today, hearing how former Canterbury College student Will Horley and a friend had taken Tramadol.

Fitness fanatic Will later fell unconscious and was rushed to hospital, where he could not be revived.

A post-mortem examination revealed his death had been from ingesting a fatal level of the drug. But the pathologist told the hearing the teenager was also suffering from pneumonia, possibly caused by inhaling some fluids, which had weakened his resistance and contributed to his death.

Tramadol is a prescription painkiller but is sometimes dangerously used as a recreational drug.

Kim, 47, of Fitzgerald Avenue, Herne Bay, says his death was "every parent's worst nightmare" and had devastated the family.

"He was a kind and caring young man who was very keen on keeping fit and had an exciting future ahead of him in the Army," she said.

"If I can influence just one teenager to reject drugs and perhaps save a life after hearing my story and what it has done to us, then that will be some crumb of comfort...." - Will's mum, Kim Webster

"But he made a stupid and ultimately very costly mistake and it shows it can happen to anyone, regardless of their upbringing.

"Young people need to know that when someone offers them something to take, they have no idea what it actually is or where it comes from, or even its strength."

Now, in a bid to persuade other young people to shun recreational drugs, Mrs Webster is planning to tell the story of the tragedy and its effect on the family in schools, including Herne Bay High, Will's former school.

"We all know drugs are everywhere these days and there is a lot of peer pressure on young people to join in," she said. "But the consequences can be heartbreaking and it is now something we have to live with for the rest of our lives.

"If I can influence just one teenager to reject drugs and perhaps save a life after hearing my story and what it has done to us, then that will be some crumb of comfort.

"I will say to them, 'imagine your mum having to stand up here and talk about it'.

"I haven't had any experience of public speaking and I don't know how I will cope. But maybe if they see what a struggle it is, that might hit home as well."

The inquest heard that the events leading up to Will's death followed a long shift at the Lobster Shack in Whitstable, where he was working last July as he looked forward to joining the Army in October.

At some stage he and fellow worker Henry Forsyth bought the Tramadol for £60 to take during the day and evening while at work.

Henry, 21, who is a student at Canterbury Christ Church University, told coroner Ian Goldup that it was very busy in the restaurant because it was the Oyster Festival weekend and they decided "to get some stuff to make the day go a bit easier".

He said he was aware Will "smoked a bit of weed" but did not know if he had taken Tramadol before.

The pair then returned to Henry's home in Olympia Way, Whitstable, in the early hours and fell asleep on sofas.

They were due to go into work the following morning but, while Henry was woken up by his sister, Georgia, Will could not be roused.

Georgia, a hearing aid audiologist, said that Will was making a snoring noise.

"We waited a bit to see if he woke up but didn't know what else to do," she said.

"When we realised he had stopped breathing,we tried to find a pulse and put him in the recovery position and called 999."

Georgia's brother Alfie attempted CPR until paramedics arrived and tried unsuccessfully to revive Will.

He was rushed to the QEQM Hospital in Margate, where he was pronounced dead, his family having rushed to his bedside.

Police Det Sgt Martin Williams told the coroner an investigation into the supply of drugs was ongoing.

He said it was taking time because the Tramadol is thought to have been bought online, so a computer needed to be analysed.

A 17-year-old boy is being investigated on suspicion of supplying the drug.

Mrs Webster told the coroner she was shocked to discover Will had taken the drug, describing him as "a typical teenager" who was sporty and excited about joining the Army.

"I knew he smoked weed sometimes but he said it helped him sleep and he promised me he would never take anything else," she said.

"It came as a complete shock to all of us that he would dabble in this kind of drug."

Recording that Will's death had been drug-related, coroner Mr Goldup offered his sympathy to the family, adding: "I can't imagine a worse thing for a parent, or the feelings you have."

The five months since Will died have done little to ease the family's pain.

As well as Mrs Webster, his father Gavin, who lives in Herne Bay, brother Jack, a 21-year-old electrician, step-father Robert, and two step-sisters, Zoe and Hannah, have all been deeply affected by his death.

"As you can imagine, Christmas was pretty grim but we had to think of the other three children," said Mrs Webster. "We just involved Will as much as we could."

Will was a keen boxer with the City Boxing Club in Canterbury and Mrs Webster is setting up a charity in his name so underprivileged youngsters can take part.

Already, £4,500 has been raised from events organised by friends.

A charity boxing tournament is also being planned with a trophy named after Will, which it is hoped will become an annual event.

"It's a way of keeping his memory alive through something he loved doing and helping other youngsters who could not otherwise afford it," said Mrs Webster.

"Will was very kind like that and would always stop to give a homeless person money, for example. He would be thrilled to think that a young person was being given that opportunity."

A charity page has also been set up to support the fundraising. Visit www.justgiving.com/crowdfunding/kim-webster.

On what would have been his 18th birthday on November 5, the family visited a memorial bench which has been sited on the foreshore at Hampton.