Police have confirmed to ITV News Central that a device left in Birmingham on the night of the pub bombings has been lost.
After almost 40 years, one of the six men jailed for the Birmingham pub bombings revisited the prison they were held in during their trial.
Hyde Park bombing suspect John Downey will not face trial after being given false assurance he was not wanted over the 1982 IRA attack.
Relatives of the families of those killed in the 1974 Birmingham bombings met with West Midland Police today to discuss the possibility of a new inquiry into the death of their loved ones. The families were told there would be no new investigation, or proceedings.
Explaining the decision, Chief Constable Chris Sims said:
There have been questions over the years why certain individuals such as the people named by the media apparently never formed part of any investigation. I want to be open and transparent today and tell you that these men had been subject to investigation in the 1970s and the 1991-94 investigation.
There was insufficient evidence for proceedings against any person.
My professional judgement is that the 1991-94 investigation was carried out to a good standard.
The families of those killed in the 1974 Birmingham pub bombings say police have told them there will not be a fresh inquiry into the attacks.
They have been speaking following a meeting with bosses at West Midlands Police today.
ITV News Central Correspondent Keith Wilkinson said there was an angry response from the victims' families, following the talks.
Brian and Julie Hambleton, whose 18-year-old sister Maxine died in the bombings, said they would continue to fight on and would now be taking legal advice.
Six men were jailed for life for the atrocity in 1975, but sixteen years later, their convictions were quashed by the Court of Appeal.
The families of those killed in the 1974 bombings at two Birmingham pubs are meeting with senior police officers to discuss whether a fresh inquiry will be launched.
Brian and Julie Hambleton lost their 18-year-old sister Maxine in the bombings - and have told ITV News Central they have never got over the loss.
Six men were arrested and the following year were jailed for life for the atrocity.
16 years later, their convictions were quashed by the Court of Appeal amid a series of public scandals about the West Midlands Police Serious Crime Squad.
It is now considered one of the biggest miscarriages of justice in British legal history.
And with the case still officially remaining unsolved almost 40 years later, the families of those lost are demanding answers.
For the Birmingham Six and their families, the sense of injustice continues too.
They felt they had been used as scapegoats in 1974 - partly to calm anti-Irish tensions in the city at the time - and have accused police of knowing who really was behind the attacks but failing to take action.
At today's meeting, which starts at 10am, senior police officers and prosecutors will discuss with the families whether a fresh inquiry is likely to go ahead.
Families of the 21 people who lost their lives in the Birmingham pub bombings 40 years ago will today meet with senior police officers to learn whether their campaign for a fresh inquiry has been successful.
West Midlands Police has been collating thousands of documents over the past few months, and examining whether new forensic techniques could be used to find those responsible.
No one has been brought to justice for the murder of 21 people in the terrorist attack on two pubs in Birmingham city centre in 1974.
One of the men who was wrongly convicted of the Birmingham pub bombings in 1974 has claimed police sent secret letters to two people the IRA claimed were actually behind the atrocity.
Paddy Hill was one of the Birmingham Six, who had their convictions quashed in 1991 having wrongly spent 16 years in jail over the attacks that killed 21 people and injured 182 others.
He told the Birmingham Mail: "I think it was about 1980 that I was told about the IRA claiming five people were involved in the Birmingham bombings. I understand two have since died. They never named anyone.
"I understand that two of these men received letters from the British Government, telling them they would not be prosecuted. One of the five has not received such a letter. The two others have died."
He added: "Many people are sweating, not knowing what's going on. It might prevent further admissions of guilt because they will now wonder if they will face prosecution."
Victims of the IRA Birmingham pub bombings have said they are "incandescent with frustration, anger and more grief" after it was claimed police sent secret letters promising immunity to two men in relation to the deadly blasts.
Paddy Hill, one of the Birmingham Six whose convictions for the atrocity were famously quashed, said two of the five people the IRA told him were involved in the 1974 bombing were informed they would not face prosecution.
It comes after a judicial inquiry was launched into the revelation that letters were sent to around 200 IRA on the runs informing them that they were not wanted by police.
Mr Hill's allegations are to be raised with the West Midlands chief constable by the local police commissioner.
Julie Hambleton, whose sister Maxine died, said: "It is almost as if we are re-living the horrors of losing our sister all over again and being slapped in the face."
A party to celebrate the release of the 1982 Hyde Park bomb suspect, whose trial collapsed last week, has been cancelled.
John Downey, a Sinn Fein member accused of planting the explosive, said he has called off the gathering in a village pub in north Donegal over concerns it was being turned into a media circus.
The 62-year-old said the party had been planned as a simple get together of family, friends and neighbours who supported him after his arrest.
Mr Downey, who denies any involvement in the bombing, said: "Some elements of the media are portraying the event planned for tonight as triumphalist and insulting to bereaved families. That was never what it was about."
Tony Blair's former chief of staff and Britain's chief negotiator in the peace process has said Northern Ireland's secret letters crisis is based on "a misunderstanding."
Writing in The Times, Jonathan Powell said discussions about "on-the-runs" were "no secret" and a "recurring issue" throughout peace process negotiations.
"The letters are statements of fact, and certainly have nothing to do with an amnesty," he added.
John Downey’s release, he goes on, "has nothing to do with an amnesty or a secret deal and everything to do with a cock-up."