The attorney general has agreed to allow an application for a fresh inquest into the death from asthma of a nine-year old girl.
He acted after hearing new evidence linking Ella Kissi-Debrah’s death to illegal levels of air pollution near her home in south London.
Lawyers acting for the family said it was a “hugely important” step.
No individual death has previously been officially linked to illegal levels of air pollution.
In August, Ella’s mother, Rosamund Adoo-Kissi-Debrah, delivered a 100,000-signature petition to Attorney General Geoffrey Cox calling for a new inquest into her daughter’s death.
He said: “I have concluded that there is new evidence which may alter the substantial truth of Ella’s death.
“I am therefore able to give my permission for an application to the High Court to request a new inquest, based on the evidential test being met.”
‘The right decision’
Ella lived in Lewisham, south London, 25m (80ft) from the South Circular road – a notorious pollution “hotspot”.
She died in February 2013 after experiencing three years of seizures.
During that time, local air pollution levels regularly breached EU legal limits. Her last fatal seizure happened during a spike in air pollution levels.
An inquest in 2014 found she had died of acute respiratory failure and severe asthma.
However, the attorney general’s decision has now paved the way for a new inquest to determine whether “unlawfully high levels of air pollution” were partially the cause of her death.
Mrs Adoo-Kissi-Debrah said: “It’s great, it’s the right decision and now we can get to the bottom, really, of the health impact of air pollution on young people.
“Hopefully if we are successful, national government, local government and individuals have to do something about cleaning up the air. It is unacceptable that children in Britain today die from asthma.”
Human rights lawyer Jocelyn Cockburn, from the