An 18-year-old mother who ran out of her home engulfed in flames died in a tragic accident, a coroner has found, despite the best efforts of a passing driver to save her.

Rachel Oye-Osei, of 86 Linkway in Raynes Park, had a history of mental health problems and appears to have been playing with a lighter and flammable hand sanitising gel while sitting on a mattress in her backyard when her coat caught on fire.

Westminster Coroner's Court heard today that after standing up, the university student then ran out of the building, leaving a trail of burnt clothing behind her.

Michael Crawley, of Carshalton, was driving along West Barnes Lane at about 12.45am on Sunday, December 29, to collect his daughter from an office Christmas party when he saw a person running very fast along the pavement in front of him who appeared to be emitting fire sparks before turning into a ball of orange flames.

He stopped the car, called an ambulance and attempted, with the help of another onlooker, to put out the flames with a blanket stored in the back of his car.

London Ambulance Service arrived at the scene at the junction with Burlington Road at 1.13am, but pronounced Rachel dead immediately afterwards.

She was in her first year studying Physical and Sport Education at St Mary's University, Twickenham, when the tragic accident happened.

She had a history of mental health problems, including anxiety and anger management issues and had been prescribed anti-depressants by her GP in September.

But she had stopped taking them soon afterwards and student counselling services who saw her on December 18 at her university assessed her to not be at risk of harming herself, as she repeatedly stated she would never leave her son.

Emma Taylor, Rachel's tutor at St Mary's University, said Rachel spoke very fondly of her son in class but said she felt disconnected from her family. Towards the end of term she fell absent from some of her lectures and said she might stop her studies to focus on her music.

She had previously told her GP she was suffering from anxiety about losing housing benefit, her relationship with her family and balancing her studies with bringing up her son.

Rachel's mum said Rachel, who moved out of her family home aged 17 and attended Ricards Lodge High School in Wimbledon, had started leaving Kai with her more and more frequently.

She did not spend Christmas with her family, which her mum said was not unusual, but she had grown concerned when Rachel didn't respond to a text inviting her to a celebration for her brother's birthday.

She called at Rachel's home on Saturday, 28 December and saw the lights were on but there was no movement inside and noone answered the door.

Just hours before her death, at midday on December 28, Rachel called police to New Malden where she told them she was distressed after trying unsuccessfully to get hold of her university tutors and she also complained of a leg pain.

Police took her to Kingston Hospital where she registered at reception but left before seeing a doctor.

Four hours later neighbours called police to reports of shouting coming from her flat.

When they arrived they found the front door open but noone was home.

A fire extinguisher lay on the lawn outside and there were items of burnt clothing in a wardrobe.

An officer returned to the flat at 8pm and Rachel admitted she had started a fire but the officer was satisfied she was not a risk to herself, and her child was with his grandmother.

Rachel told the officer she had started the fire because she was frustrated at not having heard back from her university tutors.

A post-mortem examination following her death found Rachel died of burns and smoke inhalation.

Coroner Dr Shirley Radcliffe said: "On the balance of probabilities this was a tragic accident. It could have been an experiment but there's nothing to suggest that this was a deliberate action that she did with the intention of ending her life."

Speaking after the verdict Rachel's brother Justin, 20, said: "She was very determined to make something of herself. She will be missed dearly by friends and family."

Rachel leaves behind her parents and 4-year-old son Kai, who is being cared for by Rachel's mother.

In a statement released by the family, they said: "Rachel's death was proved to be a tragic accident. It's still a shock to us.

"Rachel was very loved, will be deeply missed by her family, friends, associates and most of all her son.

"As a result from today, we can now put closure to the situation, move forward and look after her son as Rachel would have wanted."