Independent Police Complaints Commission's Deputy Chair Deborah Glass said the Hillsborough announcements were "welcome news", but added:
This is not going to be quick and easy process.
But we now have a clear path ahead with all the investigative and prosecutorial bodies working in a coordinated way to complete the full picture for the families of those who died, those who were injured and those who were traumatised by the terrible events at Hillsborough.
According to the Liverpool Echo, the Home Secretary has released the following statement on the new Hillsborough police investigation:
I am giving the IPCC new powers to investigate police misconduct, but this investigation will ensure no body with responsibility for fan safety at Hillsborough will escape scrutiny.
The Independent Police Complaints Commission (IPCC) has released a statement regarding Sir Norman Bettison's resignation.
The IPCC is currently pursuing two separate investigations involving Mr Bettison. The first is looking at "potential criminal offences" and the second at "misconduct matters".
We were not informed of Sir Norman's resignation in advance of the stories appearing in the press and the decision came as a surprise to us ...
We note Sir Norman's public statement that he intends to co-operate with our investigations.
It should be noted we can and, in this case, will investigate both criminal offences and misconduct matters after an officer has retired or resigned as it is in the public interest to do so ...
Retirement or resignation does not prevent criminal prosecution should the investigation identify criminal offences, including misconduct in a public office.
The Independent Police Complaints Commission is to independently investigate breaches of the Police and Criminal Evidence Act in the investigation into the deaths of Rebecca Godden and Sian O'Callaghan:
A Merseyside MP has said that Sir Norman Bettison should be suspended after he was named by the IPCC as it launched an inquiry in to the Hillsborough disaster.
Sir Norman, now the chief constable of West Yorkshire Police was an inspector in the South Yorkshire force in 1989.
Maria Eagle, Labour MP for Garston and Halewood, told BBC News she was concerned that;
"when he retires, because he was chief constable of Merseyside at one point, people of Merseyside, including the bereaved families and those who've been traumatised on the day, will be paying his pension, through our council tax".
Pete Weatherby QC, who represents several families of Hillsborough victims, said they welcomed the new inquiry, as some of them had already contacted the IPCC asking that it be carried out.
"After 23 years of failed inquiries there is a degree of scepticism but I think, from the families I have spoken to, they are happy this latest investigation has been announced," the QC told BBC Breakfast.
He said they wanted it to be completely transparent and to be kept informed of its progress throughout.
That is the remaining concern about it - it may be the biggest in the IPCC's history but it should also need really to be the best also.
There are other things that can be done, there can be independent outsiders brought in to ensure that the IPCC investigation is thorough and appropriate.
The families that I represent are palpably angry about the failure to bring to account those in authority that have failed in their duty.That of course starts on the day with the failings which led to this entirely avoidable tragedy.But also it applies to the outrage that followed the tragedy and they simply want people brought to book and people to be found accountable for both what happened on the day and the apparent cover-up afterwards.
Twenty-three years after the Hillsborough tragedy, an unprecedented criminal investigation into what went wrong - and the subsequent police cover-up - was ordered today.
It will be the biggest ever investigation into the police in British legal history. Former and serving officers could face prosecution - on charges ranging from manslaughter to perverting the course of justice.
What Keir Starmer at the CPS and the IPCC are both acutely aware of is the fact that the Hillsborough families have been waiting for so long already to get to this stage, they do not want to get bogged down in a very very long inquiry and then have a decision.
So the CPS will review all the evidence now that came out in last month's report to see if anybody could be prosecuted for manslaughter now, be it an individual or an organisation.
At the same time the IPCC will take on what looks to be a huge inquiry, particularly in to the cover-up. They are getting extra money from the Home Office to cope with the demand on their resources.
They are going to have to trace hundreds of former and current police officers, retired, serving deceased, some abroad - all of them have to be found and statements taken from them.
Potentially we could be looking at many years before any police officers are charged or disciplined over the cover-up element.
Margaret Aspinall's 18-year-old son James was among the 96 who died at the FA Cup semi-final, said that she is "very happy" to learn that Sir Norman Bettison, the Chief Constable of West Yorkshire Police, will be among police officers to face scrutiny by the Independent Police Complaints Commission.
He will be included and he is not going to be the only one.
Obviously they are going to look back at all the serving policemen on that day and I think that is a great thing to do because they were so many involved as part of that cover-up.
Also what we must not forget is West Midlands Police, and that they are going to be investigated as well. What did they know about the cover-up?
So I think it is very important to get this all out in the open.
Margaret Aspinall, chair of the Hillsborough Family Support Group, welcomed the announcement that the biggest-ever inquiry into police actions in the UK is to be launched in the wake of the damning report of the Hillsborough Independent Panel.
Speaking in Anfield, Liverpool, she said:
Accountability is the most important thing and responsibility, and also to make sure that this never ever happens again. I think that is very important, not just for the families but for the country as a whole because I think the country has been shamed by what has gone on over Hillsborough 23 years ago.
I think it's a shame on the country, a shame on the system and a shame on the governments and I think that has got to be changed and that is a good thing that will come from this.