What are we expecting from the Manchester Arena Inquiry report into the emergency response?

It's hard to believe that it's been more than two years since the public inquiry into the Manchester Arena attack began.

A total of 291 witnesses and experts have given evidence, 172,000 documents have been examined and today the long awaited report into the emergency response will be published.

The Inquiry Chairman Sir John Saunders will assess the adequacy of the emergency response and the circumstances of the death of each of those who lost their lives.

• Were Greater Manchester Police responsible for a breakdown in communication between the emergency services?

• Was the decision to only send three paramedics into the scene of the blast the right one?

• Why did it take the fire service more than two hours to arrive?

And, at the heart of the report, 22 lives senselessly lost, whose personalities and passions will be conveyed along with the joy they brought to their families.

However for the families of Saffie-Rose Roussos and John Atkinson, the report will be especially difficult as it seeks to address whether they might have survived with better medical care.

Could Saffie-Rose Roussos and John Atkinson have survived?

Eight-year-old Saffie-Rose Roussos from Lancashire was the youngest victim of the Arena bombing.

She was five metres away from the bomber and was carried out of the Arena on an advertising board.

An ambulance had to be flagged down in the street to take her to hospital and she was pronounced dead at 11.40pm, more than an hour after the attack.

She suffered multiple fractures, shrapnel wounds and massive blood loss and experts commissioned by the Manchester Arena Inquiry found that Saffie's injuries were not survivable. However another set of experts commissioned by Saffie's family disagree.

They believe there were missed opportunities to help her, and tomorrow the report must decide whether this was the case.

28-year-old John Atkinson was still breathing and talking when he was carried out of the Arena on a metal railing.

A member of the public wrapped his wife's handbag strap round John's leg to try and stop the bleeding but nearly an hour passed before he was seen by a paramedic.

At 23.47 he went into cardiac arrest, one hour 16 mins after the blast.

He was finally placed in an ambulance at around midnight and arrived at hospital six minutes later but he couldn't be saved.

Experts told the inquiry if he'd reached the hospital before his heart stopped he would have had a high chance of survival and that the timely medical intervention of applying effective bi-lateral tourniquets might have made a difference.

John's case is different to Saffie's because the experts all agree, however it will still be down to the Chairman of the inquiry to decide if he too agrees with their assessment.

Were Greater Manchester Police responsible for a breakdown in communication?

The police response to the Manchester Arena bombing was described as "grossly deficient" by one of the lawyers representing the families of those who died.

Peter Weatherby QC criticised Greater Manchester Police for being at the centre of a breakdown in communication between the police, fire and ambulance services.

At the core of that communication breakdown was the declaration of Operation Plato by the Force Duty Officer Dale Sexton.

Operation Plato is the code name for the pre-planned emergency response to a marauding terrorist attack. Once declared it should trigger a co-ordinated emergency response means first responders aren't allowed to enter the scene because the area is deemed too dangerous.

However Chief Inspector Dale Sexton failed to inform fire and ambulance crews that he had declared Operation Plato.

He denies being overwhelmed and forgetting to tell them and says it was a deliberate decision which he believed would save lives on the basis that he knew fire and ambulance crews would be held back if Operation Plato were in place.

Chief Inspector Dale Sexton is now being investigated by the police watchdog so it's not clear how far the inquiry Chairman will go tomorrow when it comes to commenting on the matter.

Was it the right call to only send three paramedics into the scene of the blast?

Patrick Ennis was the first paramedic to arrive at the scene of the blast and entered the foyer where the blast happened at 10.52pm.

He was joined by two other specialist HART (Hazardous Area Response Team) paramedics at 10.15pm, 44 minutes after the blast.

They triage patients but don't treat them and casualties were instead carried out of the Arena to a casualty clearing area which has been set up by other paramedics the train station concourse.

It took around 35 minutes to evacuate 38 patients, however only one actual stretcher was used all night.

The rest were carried out on billboards and railings and it fell to members of the public to treat the injured as best they could with very little first aid knowledge or equipment.

The inquiry heard lots of evidence regarding a 'disaster gap' which means the public are effectively on their own in the immediate aftermath of a terrorist attack while they wait for first responders to arrive and should therefore be better first aid trained to deal with injuries such as blood loss.

However should it really be down to members of the public?

The North West Ambulance Service have admitted more specialists should have gone in, but say it was too dangerous for operational paramedics who didn't have the protective gear or proper training.

Whether this was the right decision is something tomorrow's report is expected to reveal and Sir John Saunders must decide whether more paramedics, regular or specialist should have been sent in to help.

Why did Greater Manchester Fire and Rescue service take more than two hours to arrive?

The continued confusion over whether there was an active shooter or a secondary device meant the fire service didn't arrive at the scene for more than two hours.

In fact they were sent in the opposite direction to a fire station three miles away at Philips Park which left many of them who wanted to go and help feeling deeply frustrated.

At 00.37, two hours six minutes after the blast, the first fire engine arrived at the Arena, almost an hour after the last living casualty had been evacuated.

Even then only 12 firefighters are deployed, the same response as a house fire. So what was the reason for the delay? Were they risk averse?

The fire service say they couldn't get hold of Greater Manchester Police to find out what was going on but could they have tried harder?

Greater Manchester Fire & Rescue service accept mistakes were made and have apologised but it will be for Sir John Saunders to address the root of the problem in his findings tomorrow.

What do the families want?

For the families of the 22 who died this inquiry has been a long and difficult process. It's one thing to find out your loved one has died, but quite another to be told the circumstances of their death may have been prevented and that the emergency response may have been better.

They are tired of hearing excuses from people in positions of power and want those who made mistakes to admit to those mistakes and to say sorry.

How else can they be confident that any real meaningful change will come about which ensures a better emergency response in the future?

Admittedly the scope of what Sir John Saunders is allowed to say will have its limitations.

It is a public inquiry and therefore criminal or civil action against individuals or organisations won't be possible.

However he does have the power to stand by his promise to be "full, fair and fearless" in ensuring the families get the truth they deserve.

What do each of the emergency services say?

Greater Manchester Fire and Rescue Service said: "Part Two of the Manchester Arena Inquiry Report will look into the response of emergency services the night of the attack and we have done all we can to support this being done in the most open and transparent way possible.

"It is right that we wait for the full report, its findings and recommendations to be published before we comment."

Greater Manchester Police and North West Ambulance Service say it will comment after the report is published, to allow it to respond to any recommendations made.