Mother-of-two Karen Archard, whose body was found in Sainsbury’s car park, Chippenham, died from burns and shock after setting fire to herself, an inquest decided today.

The body of Ms Archard, 52, from Westcroft, Chippenham, was found at about 3am on August 7 2012 in Sainsbury's car park in Bath Road after firefighters had put out a blaze.

Coroner David Ridley heard she began suffering from mental health issues at the age of 26 and relapses were often triggered by moments of stress in her life.

Ms Archard, who was on anti-psychotic medication, was initially diagnosed with psychotic depression and later this diagnosis changed to schizophrenia.

In May 2012 she had a meeting with consultant physiatrist Dr Nicus Kotze, at the Hathaway Medical Centre, who reduced her medication due to health problems associated with the dosage.

He told that the court that Ms Archard had been sectioned in 2005 after her Nan suffered a stroke, but she had had no relapses since and was doing well in 2012.

He said: “She was a very placid, very kind, nice person, always on time and very approachable. I felt at that point she was stable enough.”

However on Friday August 3, when Ms Archard’s daughter Emma Clapp was at a birthday barbeque, she received a phone call from her mum who had been arrested by police.

She said the incident led to a downward spiral in her mum’s health, who appeared very tired and drained when she was released from custody the following day.

She said: “I rang the police and they said my mum was being held in custody. They said she had been arrested in a road traffic collision. She was trying to harm herself as well as others.

“My mum was always the most placid and nicest woman up until that point when that trigger hit. Sometimes she would be angry and aggressive. It was like a switch.”

Over the weekend Ms Clapp contacted the North Wiltshire Crisis Team and on Monday August 6 Ms Archard received two visits from members of the team.

This included a visit from senior practitioner William Francis in the morning and mental health nurse Julie Baker in the afternoon.

Ms Baker said: “We asked about the event on Friday with the driving incident and she spoke about having seen somebody staring at her though the window of a house.

“She felt she needed to follow this person because the person had been staring at her. I felt she was very flat and very vacant.”

Although Ms Archard agreed to a treatment review following the visits, Ms Baker said she declined daily treatment, and the following day her body was found in the car park.

Fire station manager Paul Nicholson, who is based at Trowbridge, completed a fire investigation report after the incident and described viewing CCTV images at Sainsbury’s.

He said: “There were a couple of small flashes and then a smaller flash, and then that large flash.

“This had all the signals and signs of a rapidly developing fire. It was most likely that there was some kind of accelerant used, it might not have been petrol.”

Coroner David Ridley said that he was satisfied with the opinion of pathologist Dr Hugh White who said that Ms Archard died from burns and shock.

But after hearing that Ms Archard often suffered from mood swings and heard voices in her head, he said he wasn’t sure whether she intended to set fire to herself or not.

Recording a narrative verdict, he said: “Evidence clearly points to her setting fire to herself using an accelerant. The evidence found at the scene, the lighter and the use of an accelerant in the handbag area supports the absence of third party involvement or anything suspicious.

“I have to be sure that Karen intended to take her own life and this is the area that’s troubling me. The question is unclear as to whether Karen intended to take her own life.”