A frantic knock on the door changed Kim Atkinson's life forever as a family friend brought the news that her youngest son had been hit by a car in Bristol city centre.

"I still can't really believe it has happened," she says, sat in her Hartcliffe home. "It does not feel real."

When she opened the door, the brother of her son's best friend told her: "Troy's been run over."

Kim, 39, bravely held herself together as she said: "I just went into the kitchen, grabbed the table, and said 'I'm not going anywhere.' It was as if I knew how serious it really was – it didn't really cross my mind that he would be OK."

At the end of April, 15-year-old Troy – Kim's youngest son – was killed in a hit-and-run in Bristol city centre, near the junction of Penn Street, Broad Weir and Lower Castle Street.

Later that night, as family members finally coaxed Kim out of the house and drove her to Frenchay, they were stopped by police, who wanted to take them there themselves.

"We knew then that it really was serious," said Kim, touching her fashionably cropped hair and glasses as if for comfort. "We got in touch with Troy's dad, and Troy died later that night, with his mum, dad and brothers holding his hands."

Although Kim's face betrays sleepless nights and the traces of tears, she says she has found laughter one of the best ways to get through these difficult few weeks.

"People may not think it is right," she says with a brave smile. "But it is good to remember the good things and laugh about him.

"That night, he had been to get his hair cut with his friend TJ. Thank God he had got his hair done – he was so particular about his hair.

"They had been looking at tracksuits and arguing about who could buy the one they liked first. They were just doing normal, teenage stuff, and they were the last things he did."

Kim's older sister Karen, 41, explains that they want to thank everyone who has helped them since the night Troy died.

More tearful than her sister, with her blonde hair pulled back from her face, Karen said: "The first thank-yous go to the ambulance crew, the hospital and the nurses and doctors. They were so good to us. The police have been great as well, especially our liaison officer Mark Phillips."

Family and friends have rallied around. As the Post has reported, there was a walk in Troy's memory attended by hundreds of people.

"The idea for the walk came from a barbecue organised by our friend Mange, just a few days after he died," said Kim. "It was such a great thing to do. I didn't want to go, but I did, and being amongst all those people made me feel so proud of him.

"Although this has been the worst time of my life, I have happy memories of everything that people have done for us. We have laughed and joked and have things to look back on."

Troy was a keen rugby player, playing for Nailsea and Backwell Rugby Club.

One thing Kim regrets is never going to watch him play – he always told her not to go, or to go and watch next time.

"The rugby club have been so good, and they organised a match in his memory. They also gave me a DVD of him playing so I could watch him at last," she said.

But, Kim says, girls were more important to Troy than his rugby..

Laughing, she said: "He was such a ladies' man. What can I say? He had a bus pass, and probably a girlfriend at the end of every bus route.

"We have learnt a few things about him since he died – apparently he was an agony aunt with ulterior motives, he was a great friend but always on the lookout for a new romance.

"He had so many sides," she says. "He was a monkey, but he was also very loving and caring. He chased girls, he had scraps, but I am glad he did all those things and lived his life while he could.

"When he was feeling wound up, I would point him in the direction of his drawing pad," she said. "He took out his emotions on paper. Some people have had tattoos done based on his drawings to remember him."

Troy had been a student at Withywood Community School before moving to Active8 Education in Easton.

Kim started a course at Ashley Down College two years ago and starts a psychology degree at UWE in September – to set a good example to Troy and his brothers Warren, 19, and Daniel, 22.

His brothers, along with his dad Leon, were behind the camouflage design of his coffin – to see their brother off in the style he would have appreciated.

Kim bought Troy and his friend TJ the tracksuits they had wanted, and both wore them on the day of the funeral.

In tears, his aunt Karen said: "Our family have been great, and Father Paul Bartle-Jenkins did a great job with the service.

"The funeral directors – Thomas Davis on Gloucester Road, were wonderful, looking after Troy so well leading up to and on his final journey.

"If there is anyone we have forgotten to thank, it is not because we are not grateful. So many people have done so much for us."

Troy's ashes are in a box in Kim's front room, wrapped in one of his hoodie jumpers.

"My son Warren put that on there," she says. "He thought he might get cold."

Kim plans to keep some of his ashes in an urn in her front room, and his dad is going to scatter some in Ibiza.

His brother Daniel wants to take some to his own home, and Warren plans to scatter some in the Greek resort of Malia, where he was planning to take Troy on holiday next year.

Troy's room in Kim's Gatcombe Road home is still full of his clothes and medals.

Kim says: "I don't want it to be a shrine, but it will always be his room. I am going to redecorate it this summer as I always told him I would, but I will leave all his stuff in there.

"The funny thing is that he never really slept in there – he'd normally fall asleep on the sofa watching TV."

The most important thing to Kim seems to be that her son is never forgotten.

She is talking to managers at the Castle Gate building, outside which Troy was killed, about putting a plaque on the wall.

And she is planning to hold a party every year on Troy's birthday, April 4.

"I don't want to mark the anniversary of his death," she says. "But we will have a great party every year to remember him.

"I am sure Troy will be with us. He is with us all the time, in spirit."

Last month , Mohammed Ahmed, 18, of Eastville, appeared at Bristol Crown Court charged with causing Troy's death by dangerous driving.

Ahmed also faces charges of taking a vehicle without consent, failing to stop after an accident and driving without insurance. He was remanded in custody until September 7.