The Attorney General will apply for a fresh inquest to be held into the deaths of 96 fans in the Hillsborough disaster 23 years ago.
Dominic Grieve QC said he will apply to the High Court to have the verdicts of the original hearing quashed so a new one can be held.
Liverpool MP, Steve Rotheram, a long campaigner for justice for those killed at the match said the announcement was "one of the biggest steps forward in the fight for justice for the families in 23 years".
The move comes after a damning report into the disaster laid bare a cover-up which attempted to shift the blame for the tragedy on to its victims.
Grieve said his consideration of the evidence was far from over, but he was taking the exceptional step of indicating he must apply for new inquests to be held on the basis of the evidence he has already read.
Ninety six Liverpool supporters died in the crush at Sheffield Wednesday's Hillsborough stadium on April 15 1989, where their team were to meet Nottingham Forest in an FA Cup semi-final.
Grieve said: "My consideration of the evidence is far from complete but, given the anxiety further delay may cause the families affected by the Hillsborough disaster, I have decided to take an exceptional course and state at this stage that, on the basis of what I have already seen, I have determined that I must make an application to the court.
"In doing so, I should make it clear that further work will need to be done before any application can be made.
"In particular, there was not one inquest but 96.
"My current view is that I will apply to have every one of those 96 inquests quashed."
He went on: "I believe that these deaths, arising as they do from a common chain of events, should all be considered afresh.
"However, before reaching any final view on the scope of the application, I want to give the families affected the opportunity to make any representations in respect of the family member or members they lost.
"I will therefore be in contact with each family seeking views."
Any criminal proceedings would have an impact on when a new inquest could take place, he added, but this would not affect the timing of his application to have the original verdicts overturned.
The application was "not simply a matter of putting the Hillsborough Panel Report before the court", Grieve said.
"The application will need to be fully prepared and the evidence that underpins the report's findings will need to be carefully considered.
"I want the application that is made to be as persuasive as it can be."
Prime Minister David Cameron said last month that Grieve would review the highly-critical report to decide whether to apply to quash the original, flawed inquest and apply for a new one.
It was clear there were "significant issues over the original inquest", Grieve said.
But he admitted the procedure "will take some time" and acknowledged that "the wait for truth and justice has been long and unspeakably painful for a great many people".
It was "inevitable" that the taxpayer was going to pay a significant amount of the costs involved in any new inquest, Grieve added.
Rotheram said: "The undeniable fact is that the original inquest was unsound and this application, if successful, will mean that evidence will be able to be heard after the 3.15pm cut off imposed by the original Coroner in the 1989 inquests.
“For the first time in over two decades, all the evidence can now be reviewed into the disaster and potentially a new verdict recorded on the death certificates of the deceased.
“At long last, the full horror of Hillsborough will be on the public record alongside the names of the people and the organisations that are accountable for what happened.”
“The families’ heartache has been well documented but what is less well known is that some families have refused to pick up the death certificates of their loved ones who died on that day.
“I made clear when I became an MP that for as long as I represented Liverpool and the continued fight for truth and justice for the 96, I would never accept the verdict of accidental death on the death certificates.
"Today’s announcement provides us with the possibility for different verdicts which the families have always believed should have reflected the unlawful killing of their loved ones.
“There is no guarantee that the High Court will accept the Attorney General’s application but I am confident that the British judicial system will not allow one of the greatest injustices of the 20th century to perpetuate any longer.
“With the report of the Hillsborough Independent Panel last month, the IPCC launching their investigation last week and now the Attorney General’s announcement today, the momentum is well and truly behind the fight for justice.”