FORENSIC scientist Emma Wilson, who specialises in fire investigation, agreed with Mr Peterson’s findings.

She formed her opinions from photographs, CCTV footage and the statements of witnesses.

Kim Buckley, 46, her daughter Kayleigh, 17, and six-month-old granddaughter Kimberley died in the fire which ripped through their home at around 3.30am on September 18 last year.

Kayleigh’s boyfriend Carl Mills, 28, of no fixed abode, is charged with their murders. He denies all charges.

Ms Wilson backed up Mr Peterson’s opinion that the fire was started deliberately using a naked flame in the porch and agreed a discarded cigarette did not start it.

She said precise conditions would be needed for a cigarette to catch alight.

She added that while loose rolling tobacco was found in the house, in her view it would not be a viable ignition source.

Asked by prosecutor Gregory Bull QC how confident she was about that, she said: “I’m very happy with that assertion.”

Jury members were shown photographs of a tent Carl Mills slept in on a grass in front of the home.

It had a burn mark on the tent wall as well as a burn on the remains of an inflatable mattress inside.

Ms Wilson said these would not have been caused by radiating heat from the house fire and added she was sure they were caused, possibly with the use of an accelerant like lighter fluid, before September 18 because they were visible in photos of the fire taken that morning.

She will continue her evidence today.

Proceeding.