The worst horror for any parent is for their child to die before they do. For the person you have produced, and seen change and grow, to suffer and expire is utterly heart-rending. It offends the natural order of things: we expect the older generation to die off and the younger one to spring up behind them in their turn.

Rosamund Kissi-Debrah has had to suffer that awful fate. She lived near the South Circular Road in London, where she brought up her daughter, Ella, and her two other children. Ella lived almost her whole life in a constant atmosphere of air pollution. From 2010, she began to show serious signs of severe, unstable asthma. Over the next three years, she was admitted to five different hospitals on 27 separate occasions. In 2013, tragically, she died at the age of nine.

The inquest found that Ella had died of ‘acute respiratory failure and severe asthma’. But that hardly answers the question; it is like saying she died of a bullet wound but not enquiring into the circumstances of the gun being fired.

The purpose of an inquest, defined in Coroners and Justice Act (CJA) 2009 s5(1)(b), is to ascertain ‘how’ she died, but also – where necessary to avoid a breach of a right under the European Convention on Human Rights – ‘in what circumstances the deceased came by his or her death’ (s5(2)).

Expert evidence now makes the family’s case that Ella’s 27 hospital admissions coincided with peaks in nitrogen dioxide and particulate matter where she lived. Subsequently, Rosamund Kissi-Debrah succeeded in both obtaining an attorney general’s reference and an order of the High Court quashing the first inquest.

At the fresh inquest, a coroner will have to write a report if anything revealed by the investigation 'gives rise to a concern that circumstances creating a risk of other deaths will occur, or will continue to exist, in the future' (CJA 2009 Sch 5 para 7(1)(b)). The report must go to ‘a person who the coroner believes may have power to take such action’ (Sch 5 para 7(1)), who must then respond in writing.

This has enormous significance for the UK government’s repeated failure to act on illegal levels of air pollution, as shown in the ClientEarth judgments in both the UK courts and at the European Court of Justice. In the Administrative Court, in R (ClientEarth) No 3 v Secretary of State for Environment, Food and Rural Affairs and others [2018] EWHC 315 (Admin), Garnham J said:

Ella’s case has been a ground-breaking legal action as well as a heart-breaking personal one. Illegal levels of air pollution are increasingly recognised as the number one public health issue of our time, but this could be the first time an inquest really has to grapple with the possibility that a death resulted from air pollution.

The government is, very belatedly, taking steps to reduce air pollution but it still remains way above maximum legal levels in many cities. The issues being addressed here are therefore of very wide public significance.

Against all the resources of the Government Legal Department, Ella’s family still faces the inequality that is the system of legal aid for inquests. Much of the legal work has been crowdfunded and would, of course, not be possible without the serious commitment of her solicitor, Jocelyn Cockburn of Hodge Jones and Allen. It is wholly wrong that there is such a level of disparity in the resources available to the bereaved compared with the state.