THE senior coroner for Birmingham and Solihull Louise Hunt announced the decision after holding several review hearings and receiving "significant" new information about the double bombing on November 21, 1974.
During the recent hearings, families of some of those killed in the blasts in the Mulberry Bush and Tavern in the Town pubs put forward a claim that the British state had knowledge of the attacks planned by the IRA before they were carried out.
The double bombing, which destroyed the Mulberry Bush pub at the base of the city's landmark Bullring Rotunda and the underground Tavern in the Town, is widely acknowledged to have been the work of the IRA.
It was the worst terrorist attack in Britain until the London 7/7 bombings and left 21 dead and 182 injured.
Those responsible have never faced justice and the only men to be tried for the crime - the Birmingham Six - had their convictions overturned by the Court of Appeal in 1991, after a botched investigation by West Midlands Police.
Setting out the reasons for her ruling, Ms Hunt said there was evidence that West Midlands Police had missed two potential warnings of the bomb attacks, including a comment made by men linked to IRA that "Birmingham would be hit next week".
That overheard conversation was reported to police on November 10 1974, but Ms Hunt said there was "no indication that the police took any active steps in response to it".
On the day of the attack, a second tip-off to the police was not followed up, she added.
Ms Hunt went on: "I have serious concerns that advanced notice of the bombs may have been available to the police and that they failed to take the necessary steps to protect life."
Concluding, she said: "This is specifically in respect of the two matters I have identified.
"It is only in respect of that issue that I consider there is sufficient reason to resume an inquest to investigate the circumstances of these deaths.
"So I am satisfied that the inquest should be resumed."
She said claims that police were protecting a mole in the IRA cell were unfounded, and neither did the emergency services response that night contribute to the deaths.
Grieving relatives of those killed in the bombings believe new inquests are their best chance at filling the void left in their lives by the deadly attacks.
Paul Rowlands lived in a city block of flats with parents John and Iris Rowlands, while older brother Steve was away serving in the RAF, when he found out his father had died.
As an 11-year-old he remembered lying in bed on the night of November 21 1974 and hearing "a knock at the door".
His father John Rowlands, a 46-year-old electrician, had been drinking in the Mulberry Bush when the first bomb went off.
"There were two policewomen," Mr Rowlands recalled.
"They gave the news to my mother and left.
"She was just sitting on the chair, rocking back and forwards saying 'I can't believe it'."
The rigging manager, who now lives in Lye in the West Midlands, added: "My brother had it very difficult.
"He had to identify the body.
"There was no form of support. It's left a void in our lives."
Jamie Hamblton, the sister of one of the victim's has demanded the "gutless" individuals responsible give themselves up, in an angry confrontation with a former IRA intelligence director.
Julie Hambleton issued a stinging riposte to Kieran Conway after he claimed the bombers were "relatively blameless" and would never face justice despite their identities being widely known.
Ms Hambleton, whose older sister Maxine was among the 21 killed by the blasts in two busy city venues in 1974, was taking part in a BBC Radio 4 Today discussion with Mr Conway.
He said that while the carnage was "appalling on every level" and "immoral", the fact that warnings were reportedly attempted - but thwarted by vandalised phone boxes - reduced the blame.
"I take the view that appalling and all as the bombs were, the volunteers who carried them out were relatively blameless in that their only fault was that they carried out the instructions of their commander," he told the programme.
"Their only fault was that they didn't - and this would have been elementary, I was trained in bomb planting myself and planted a few in my time - in advance check that they had working phone boxes and a back-up in case of difficulty.
"I don't view IRA volunteers as murderers; I view them as people who participated in a just war."
He said there was "no prospect of convictions" because there was "simply no evidence" and it would be very hard to extradite individuals to the UK from Dublin.
"The only way that there could be convictions for the Birmingham bombs would be if one or more of the bombers were to present themselves to the UK police station and make full confessions. I don't believe that will happen."
His words met a furious response from Ms Hambleton, who said he was "delusional" and gave a graphic description of the injuries suffered by victims.
"Men - or women, we don't know - planned, prepped, put together bombs, walked into two pubs and then claim that it was an accident? I have never heard such a load of utter rubbish," she said.
"How dare he be on the other end of the line and make such claims?
"It was 'an accident', it was 'approved', he doesn't consider them to be murderers?
"I wonder if one of his kids was killed beyond description - when all their skin has literally been stripped off their body, they've got no legs, they've got no arms, you can't recognise them by their face because their injuries are such that they've already been partially cremated - how dare he make such harrowing and horrendous statements over the airwaves.
"If they were soldiers they would have principles and discipline. Where was their discipline? They denied doing it in the first place, which showed they knew they'd done wrong.
"It just shows how gutless they are because if they had any kind of morals or humanity they would actually do exactly what Kieran Conway has said, and walk into the local police station and put their hands up and say 'I did it and I'm proud I did it and I'm coming in to admit to what I've done'."
She told the programme she had deliberately avoiding having children because she would not be able to bear the trauma of losing one.
"But we have got to fight for future generations because otherwise anyone can kill anyone and never have to fear about facing the law and doing time for the crimes they commit.
"If we don't fight for truth, justice and accountability then what we are basically allowing is for any future terrorist group to come to any of our great cities and kill with impunity.
"If we don't fight - and the authorities can't be bothered - as a society we are going to allow anarchy to rule okay."
