A botched IRA warning call led to the deaths of 21 people unlawfully killed in the 1974 Birmingham pub bombings, an inquest jury has found.

Two massive detonations caused what one witness described as “pure carnage”, ripping apart the packed Mulberry Bush and Tavern in the Town pubs on the night of November 21, killing 21 and injuring 220 more.

The 11-member panel, which sat for almost six weeks and deliberated for almost five hours, unanimously concluded an inadequate warning call by the Provisional IRA, which carried out the attacks, cost the stretched police vital minutes.

The six female and five male jurors also determined the victims were unlawfully killed.

Birmingham pub bombings inquest
The bomb-blasted Mulberry Bush pub (PA)

They also found there was “not sufficient evidence” of any failings, errors or omissions by West Midlands Police’s response to the bomb warning call, or in regards to two alleged tip-offs to the force, giving advanced warning of the blasts.

Qualifying the jury findings in relation to the police’s response, the panel’s foreman told the court: “The decision was based on the balance of the evidence provided.”

The families of those killed have called on the police to “redouble” efforts to bring those responsible to justice.

Giving conclusions, the jury found a coded telephone warning by the IRA to the Birmingham Post and Mail at 8.11pm was wholly inadequate.

The call, made to newspaper telephonist Ian Cropper, gave the bomb locations as the famous Rotunda building and the nearby Tax Office in New Street, making no mention of pubs.

Police first on the scene searched the Rotunda office block, wrongly believing one of the bombs was inside.

In evidence, it emerged frontline officers had no standardised training or procedures to work from when dealing with bomb warnings.

One detective told the inquest that bomb threats were dealt with “lightheartedly”.

Birmingham pub bombings inquest
The entrance to the basement Tavern in the Town pub (PA)

During evidence, medical experts said those killed suffered “unsurvivable” injuries but that hospital medical care had been “very impressive”, even by modern standards.

However, there were not enough ambulances to go around, and taxi drivers had to take casualties to hospitals.

After taking conclusions, coroner Sir Peter Thornton QC offered “heartfelt appreciation” to all those who helped that night, from the police and firefighters to taxi drivers and members of the public.

He said: “These were the people of Birmingham shown at their best – brave, generous, selfless.

“A genuinely positive side of humanity in contrast to the devastation and destruction all around them.”

In evidence, jurors heard officers responding to the bomb calls were not told by police control that the warning had contained a recognised IRA code word, used previously in a successful bomb attack on the Rotunda complex.

Birmingham had also been “denuded” of police that night, after officers were pulled away to bolster security for IRA bomber James McDade’s funeral procession in Coventry.

There were just 15 officers covering the whole of the city centre.

One of the first on the scene, retired Pc Derek Bradbury, said “we were told it was the Rotunda”, and he and colleagues’ first thought had been to clear the office block.

There was no evacuation of the Mulberry Bush pub, located around the side of the Rotunda’s base, where eight people died.

Nor was there any attempt to clear the surrounding area, or cordon off the street, which was still open to traffic.

Best friends Neil “Tommy” Marsh, 16, and Paul Davies, 17, two of the youngest victims that night, were right outside the Mulberry Bush when the bomb went off, while a double-decker bus full of passengers was peppered with shrapnel from the blast.

Birmingham pub bombings inquest
Paul Davies died outside the Mulberry Bush pub (Family handout/PA)

Pc Bradbury said a perimeter would have been “a brilliant idea” if you had the numbers, but there were “not enough” officers sent to the scene to do it.

His colleague, former Pc Rod Hazlewood, described manpower as being at “half-strength”.

Jurors heard the first officers at the scene were already in the lift inside the Rotunda when they felt the first bomb go off.

Ex-sergeant William Pederson, who was in the Rotunda, said had he known it was a coded warning, “the advice would be to evacuate” rather than search, while Pc Hazlewood said he also “would have expected” to have been told.

Officers said they were never given laminated pocket cards on how to deal with bomb threats, despite senior officers claiming they were handed out.

Retired detective constable John Plimmer, in his evidence, also said bomb warnings were “treated lightheartedly”, though he later said all threats were treated “seriously”.

The first bomb went off at the Mulberry Bush at 8.18pm, followed by the blast at the Tavern at 8.20pm.

The warning call was passed from the force control room in the city to beat officers at some time around 8.14pm.

Six officers did get to the Rotunda before the bomb went off at the Mulberry Bush, but most went inside the office building to start the search.

Two officers were still running to get along New Street when the bomb at the Tavern in the Town exploded, killing 11 people.

But in any case, the Tax Office was located above the basement pub, and accessed by a different entrance.

Birmingham pub bombings inquest
The Mulberry Bush pub, located in the base of the Rotunda building (PA)

The inquests threw up dramatic evidence when a former IRA member named four of the men he claimed were involved in the bombings as Seamus McLoughlin, Mick Murray, Michael Hayes and James Francis Gavin.

The man, identified in court only as “Witness O”, said he had been authorised to give those names by the current head of the IRA in Dublin.

McLoughlin, who was said to have planned the operation, died in 2014, and Gavin in 2002, while Hayes, who is alive, has previously said he took “collective responsibility” for the bombings.

Murray, who died in 1999, is said to have called in the botched warning, giving the code word “Double X”, but always maintained it had been “a proper warning”.

The then IRA head of intelligence in Ireland, Kieran Conway, in his evidence, also described the victims’ deaths as “accidental” and not “murders”, in an “IRA operation that went badly wrong”.

Former MP Chris Mullin, who helped free the Birmingham Six, was called a “disgrace” by Julie Hambleton, who lost her older sister in the bombings, when he refused to name any of the still-living bombers during his evidence.

He had to be escorted from the building by security staff and police.

He later said: “In order to track down the bombers I had to give repeated assurances, not only to the guilty, but to innocent intermediaries that I would not disclose the names of those who co-operated with my inquiries. Had I not done so, no-one would have co-operated. Far from obstructing justice, I am the person who helped clear up the mess.”

Jurors ruled out that the police had any forewarning of the bombs, after hearing evidence of two alleged overheard conversations – one involving IRA prisoners, and another between Irish men in a Birmingham pub.

The panel also heard how key evidence is still missing, including a “pristine” pistol found under a nearby bench, or was never collected, such as CCTV in the Rotunda.

A third unexploded bomb, found a mile away by Barclay’s Bank in Hagley Road, was misplaced by police, while the force’s control room call tapes from the night were also overwritten.

Birmingham pub bombings inquest
Julie Hambleton speaking to media after the inquests (Aaron Chown/PA)

The inquests, at the civil courts building in Birmingham, came about after years of campaigning by relatives of the dead for a full account into what happened that night.

The pub bombings were the deadliest post-Second World War attack on the British mainland until the 7/7 London terrorist attacks in 2005.

A botched investigation by West Midlands Police led to the 1975 convictions of the Birmingham Six, but their convictions were quashed by the Court of Appeal in 1991.

Ms Hambleton said before the hearings that bereaved families wanted “truth, justice and accountability”.

West Midlands Police Chief Constable described the pursuit of any suspects in connection with the bombings as “a very active investigation”.

Asked if, as was suggested in the inquest, the Good Friday Agreement had blocked any realistic prospect of bringing the killers to justice, he said it would not “prevent” that process.

He said: “This is simply about the evidence.

“The criminal investigation will take the direction it is going to take.

“We will bring people to justice within our ability to do that.

“I don’t see anything in terms of any political arrangement that prevents us to carrying out that enquiry.”