Watch: Home footage of Emily Salvini who was the victim of an arson attack in Caversham in May 1997

Emily Salvini was just seven years old when an arsonist torched her family home on Hemdean Road.

Her brother Zach alerted the mother Katie and they escaped with burn injuries, but they were unable to get to Emily in time and she died of smoke inhalation.

With the trace to find Emily’s killer running cold two decades later, Ms Salvini – still dealing with the grief of losing her first-born child – says she blames herself for being unable to save her.

Emily Salvini was the victim of an arson attack at her home in Caversham but her killer remains at large two decades later

“Losing Emily has been the devastation that has eclipsed everything else," her mother explained.

"Emily deserves justice. She was a pure delight to be around. She was sweet, she was kind and she was gentle.

“Your ways of blocking the pain become more efficient, but I don’t think we will ever get closure.

“Emily is gone. She has been murdered. People need to see some form of justice. Her life shouldn’t have been taken. She was going to be the prettiest girl in the world.”

Emily’s killer cut the telephone lines to prevent the neighbours from calling the emergency services in the early hours of May 3, 1997.

L-R: Peter Beirne, head of major crime review team for Thames Valley Police, Zach Salvini, Emily's brother, and mother Katie

The unknown arsonist poured petrol through the letterbox, followed by a match, sending the house up in flames days after the tyres on the family car had been slashed.

Her brother Zach, who was three at the time, recalls the tragic memory of Emily’s death, adding: “It is my earliest and saddest memory. I remember waking up and being distressed.

“I was crying and I woke mum up. She sat me on the bed and she went to the door and tried to open it, but it pushed her back as soon as she opened it.

“She started screaming and panicking for Emily and then she started screaming her name over and over again.

Zach Salvini described his sister's tragic death as his 'earliest and saddest memory' at an appeal at Reading police station

“If they were to catch the person I would have nothing to say to them, but for the purpose of this appeal I would urge them to come forward and I appeal to their conscience.”

Ms Salvini and her son managed to escape, but required weeks of treatment for burns at Stoke Mandeville Hospital.

Police made several arrests in the months after Emily’s death, but there has so far been insufficient evidence to charge somebody with her murder.

Peter Beirne, head of Thames Valley Police major crime review team, said: “It is difficult to comprehend why anyone would want to set fire to the home of a young family.

“The person will have had this horrific act on their conscience for two decades and there has to be a possibility that they have confided in someone.

“Even if you think the information is insignificant, please come forward so we can investigate.

“Two decades may have elapsed, but we are still pursuing this case.

"The person responsible for these atrocious crimes will be going to jail for a very long time and we are keen to make sure that justice is done for Emily and her family, who have had to live with the unbearable grief of her death."