Almost a year since the Grenfell Tower fire inflicted loss on a scale unheard of in modern history, the inquiry into its origins is to begin.

Nine days of commemoration for 72 victims – including one former resident who died in January – are to be held as a poignant overture to what will likely be weeks of highly technical evidence hearings.

Here, we examine who is involved in the process and what is at stake.

Tributes to the victims at Notting Hill Methodist Church near Grenfell Tower (Isabel Infantes/PA)
Tributes to the victims at Notting Hill Methodist Church near Grenfell Tower (Isabel Infantes/PA)

– What happened at Grenfell Tower?

Shortly after midnight on June 14, a small fire broke out in a flat on the fourth floor of the 24-storey block, which quickly engulfed the entire building.

It became the most costly human tragedy in a generation, killing 71 people and leaving hundreds more homeless.

– Why was a public inquiry launched?

Widespread anger followed the disaster as it became clear that residents of Grenfell Tower had long warned the building was blighted by fire safety risks.

The spread of the blaze had apparently been accelerated by the material used in a recent £8.6 million refurbishment, raising troubling questions about how it came to be installed.

By late June, Prime Minister Theresa May had appointed Sir Martin Moore-Bick, a retired Court of Appeal judge, to head a public inquiry into the tragedy so these concerns could be answered.

According to the website, the probe will “establish the facts and will make recommendations as to the action needed to prevent a similar tragedy happening again”.

– What will the public inquiry be examining?

Sir Martin’s probe will be split into two phases, the first of which has been timetabled to last until late October.

Phase one will examine the immediate causes of the fire and how it came to spread with such deadly effect. This will involve evidence from those who escaped the blaze and the firefighters who battled it, alongside expert evidence.

This strand of the inquiry has been given priority so an interim report can be published as a matter of urgency, in the hope it will highlight any major safety issues which need to addressed at other high-rise blocks.

In the second stage, the deeper cultural issues underlying the fire’s causes will be put under the microscope.

Why residents’ warnings were ignored, the response of Kensington and Chelsea Council and central Government in the aftermath of the fire and the work of the emergency services will be among a catalogue of issues explored.

For the second stage, Sir Martin will have a panel sitting alongside him during hearings. This format change came after bereaved families and survivors exerted sustained pressure on the Government amid misgivings about Sir Martin’s suitability as the sole authority to investigate a disaster of such cultural complexity.

The fire swept through Grenfell Tower in west London on June 14 last year (Natalie Oxford/PA)
The fire swept through Grenfell Tower in west London on June 14 last year (Natalie Oxford/PA)

– Who will be involved?

A total of 533 individuals have received core participant status in the inquiry, including 21 children, along with 29 organisations, including 12 public bodies, 23 commercial organisations and five trade unions.

Core participants are afforded access to key evidence, the right to make opening and closing statements at certain hearings, to suggest lines of questioning to the probe’s counsel and, “with permission”, to question witnesses themselves through their lawyers.

All survivors of the fire have been granted core participant status along with key authorities such as the block’s owners, Kensington and Chelsea Council, and the body which managed it.

– What could the ramifications of the inquiry be?

Sir Martin has made clear that he will not “shrink” from making findings that could form the backbone of a criminal or civil case.

This means that, while he will not be able to apportion legal liability, he could potentially outline allegations made in future cases.

He will write to the Prime Minister making his recommendations once the inquiry concludes.