Image source, PA

It's been a busy day for PSNI Chief Constable Simon Byrne as he faced the public on the force's data breach crisis for the first time.

It came after a mammoth four-hour meeting of the NI Policing Board, where he was questioned by board members.

He apologised and revealed that there are unverified claims dissident republicans have the information leaked in the data breaches.

With that we're bringing our live coverage to a close, but you can follow all the latest on this story on the BBC News website.

Today's live page was written by Jess Lawrence, Emily McGarvey, Amy Stewart and Jake Wood.

Before we end our coverage, here's a quick recap on what we learned today.

• There are claims dissident republicans have a list of PSNI staff information after two data breaches, but these claims are unverified according to Chief Constable Simon Byrne
• He says he's deeply sorry for data breaches he described as being of an industrial scale
• Byrne says he will not step down during an "unprecedented crisis"
• An investigation has been launched into what happened, with Byrne acknowledging the PSNI could face huge financial penalties

Policing Board member Gerry Kelly assesses the situation after listening to Simon Byrne

"The situation is dire. We are talking about 10,000 people affected and their families," he tells the media.

Mr Kelly says the staff are of primary concern, and he acknowledges the different levels of risk posed to different types of staff members who now live in a "new reality".

When asked if Simon Byrne has the confidence of the public, Mr Kelly says: "This thing can't be brought down to one person.

"If you ever wanted a test, to test a chief constable's leadership, then that is being given to them now. How quickly they move, and what changes they make... will shape the public's trust moving forward."

The Ulster Unionist Party's Mike Nesbitt says some clarity was provided on how the data breach came about.

He says it was partly a systemic error with the use of excel spreadsheets, and partly human error wherein a number of people saw the data before it was published.

There are three main areas of focus for dealing with the crisis, Mr Nesbitt says.

The safety and security of officers, and resources available to deal with this is the first.

He says that budgets will have to stretch to allow these processes to happen.

The second is the financial implications due to personal data breaches, adding that it could be in the millions.

The flow of intelligence is the third area of concern, Mr Nesbitt concludes.

A number of officers who have contacted him say they do not want to contact their line managers about the breach as they have lost confidence in the force.

Policing Board member Mark H Durkan says the claim that dissident republicans have information on police officers in the wake of the data breaches is "very alarming" and "sadly inevitable".

"Whether or not they do (have that information) is another matter, but however that has to be the assumption now," he says, adding that he fears "over the next couple of days we could see the outworking of that in terms of attacks on officers".

"I can only imagine the stress this is causing some families right across the organisation but particularly for officers from nationalist backgrounds who have been subject to a higher level of threat over the years," he says.

We're beginning to hear from some Policing Board members as they leave.

Alliance assembly member Nuala McAllister describes it as a "long and intense" meeting.

Two key issues stuck out, she adds, including the welfare and safeguarding of officers, and accountability.

McAllister also refers to the claim that dissident republicans may be in possession of the data uploaded, saying that it will not "come as a shock but a worry to many".

It is important that police have the space to assess that threat to ensure people are protected, she says.

Charlotte Gallagher
BBC News correspondent

The first priority for the police force now is dealing with the concerns of its officers and their safety.

Secondly, they will be seeking to clarify the claims from dissident groups that they have their hands on the list.

Thirdly, they will be ensuring that this can never happen again going forward.

A short while ago Police Service of Northern Ireland (PSNI) Chief Constable Simon Byrne finished answering questions about two major police data breaches.

If you missed it, here are the main points:

• Byrne says he is "deeply sorry" for the industrial scale data breach
• He says claims that dissident republicans have a list of PSNI staff information are not verified
• Byrne reiterates that he will not step down as calm heads are needed during this "unprecedented crisis"

• An investigation has been launched and due process will be taken if misconduct is found, he says
• He also acknowledges the huge financial penalty the police may be liable to pay due to the data breaches
• Priority is the welfare of staff and officers caught up in the systemic failure, Assistant Chief Constable Chris Todd adds

Image source, PA Media

Those of you watching the stream will know there were some technical difficulties which made it tough to hear everything Byrne said - but we've been going back through the recording to get more detail.

He says "an early worst case scenario that we have been dealing with is that third parties would attempt to get this data to intimidate, corrupt or cause harm to our officers and staff".

One of the key points the PSNI chief constable made was around the claim that dissident republicans are in possession of information about officers which has been circulating on WhatsApp following the data breach.

Byrne said the claim was unverified but that the force had been "advising officers and staff about how to deal with that and any further risk that they face".

In the final moments before the press conference ended, Assistant Chief Constable Chris Todd said a systemic failure led to the data breaches.

He said there needs to be consideration of those involved in the incidents, and they are getting full support.

The priority is the welfare and well-being of the staff and their families, he added.

Towards the end of the press conference, the chief constable says there is an investigation under way into the breach, and if misconduct is found, due process will be taken.

"There is a huge amount of scrutiny on a small number of individuals in relation to this matter, and those are being dealt with in the manner you would imagine when we suspect misconduct."

He added: "We have to recognise that we are liable to a huge amount of financial penalty."

Shortly after that the press conference came to an end.

In relation to the theft of a police issued laptop and radio from a car in Newtownabbey last month the chief constable said they have not been recovered, but they would not be of use to the thieves.

"We have means of wiping those devices remotely... so we are confident that information on them would not be accessible by a third party."

Assistant Chief Constable Chris Todd said the information "came through to our security on the 27th and I dealt with it immediately after that, as soon as it came to my attention".

“Then we informed the ICO (Information Commissioners Office)

“The gap in between is part of an ongoing investigation, it’s not clear to be frank at the moment as to why there was a delay and that is of concern to me and that is something we will be looking very closely at.

“In terms of the individual concerned, I have to respect the rights of them because they are involved in a process and I am not in a position to give any personal information about them out at the moment.”

Simon Byrne says that he and the senior leadership team apologise "unreservedly" for the breach.

He says he has personally spoken to staff in the last number of days who have a "range of emotions".

Some are pragmatic, whereas others are anxious, frustrated and angry.

“You can only imagine the unconsciable horror as people start to realise that maybe a loved one is put in jeopardy by what they are seeing," he said.

He said he had personally spoken to staff and officers across the organisation and said emotions ranged from pragmatism, to “people being anxious, frustrated and really, really angry”.

Image source, PA

The chief constable bats away questions over his position.

"Leadership is not about walking away, its facing up to responsibility. We need consistency and calm heads to lead us through an unprecedented crisis," he says.

The chief constable confirms the police have not rehoused anyone yet over the data breaches.

Some officers have expressed concerns about their security in the aftermath of the breaches.

Simon Byrne says there will be human and reputational consequences of what has happened, which he describes as an "unprecedented crisis".

He told a press conference: “One of the things we’ve done under the leadership is establish a group to look at real-time concerns about threat and risk.

“We’ve had over 500 referrals to that service, which is real-time triaging the level of risk that we perceive officers to be facing and then we’re offering them that advice.

“We have not yet redeployed anybody, for example, from their home, we’re taking steps this afternoon to reassess in some cases, which I won’t go into for operational reasons, whether we need to redeploy some specialist officers away from the usual place of work to a new location.”

In relation to the claim that dissident republicans have the PSNI staff list, Mr Byrne says the PSNI hasn't "been able to verify the substance behind that claim".

"We recognise there is now an issue of trust in regards to the public's trust," he adds.

Image source, PA Media

Simon Byrne says he is deeply sorry about the breach of data on an "industrial scale" which is now in the public domain.

A key priority is now remaining alert to the safety and welfare of both officers and staff.

He is speaking at a news conference in Belfast.

Read more here.

PSNI Chief Constable Simon Byrne has at the NI Policing Board headquarters in Belfast and the press conference has started.

You can watch live by pressing the play button at the top of this page although the stream is currently encountering some technical difficulties. We'll also bring you text updates on what Simon Byrne says right here.

Julian O'Neill
BBC News NI Home Affairs Correspondent

At today's Policing Board meeting the chief constable was asked who may be in possession of the list of leaked workforce names.

It follows two data breaches - one where the details of all 10,000 PSNI staff were posted online in error, and a second where documents and a laptop were stolen from a vehicle.

It was indicated at the Policing Board that dissident republicans are claiming - and, it is stressed, claiming - to have the list.

We are still waiting for the press conference but expect it to start in the next 15 to 20 minutes.

Image source, Pacemaker

With the Policing Board meeting over after almost four hours behind closed doors, we should have the press conference shortly.

Here's a reminder of what today is all about after the PSNI revealed in the past days that there have been two major data breaches featuring the personal details of serving PSNI officers:

• On Tuesday, the details of all 10,000 PSNI staff were revealed in error following a Freedom of Information (FoI) request from a member of the public, who had asked for a breakdown of officers' ranks and staff grades

• It was taken down from a website after two-and-a-half hours
• Less than 24 hours later, the police revealed another data breach had taken place in July
• Documents, including a spreadsheet with the names of 200 officers and staff, and a police laptop and radio were taken from a private vehicle in Newtownabbey, County Antrim
• PSNI Chief Constable Simon Byrne cut short his holiday to attend an emergency meeting of the NI Policing Board - he is due to face the media shortly, the first time he has publicly answered questions about the crisis