A man has been arrested in connection with the murders of 21 people in the 1974 pub bombings in Birmingham.
The arrest comes just days before the 46th anniversary of the two deadly November 21 blasts which ripped apart the Mulberry Bush and Tavern in the Town pubs.
West Midlands Police said officers from the West Midlands counter terrorism unit, working with colleagues from the Police Service of Northern Ireland (PSNI), arrested a 65-year-old man at his home in Belfast on Wednesday.
The man was arrested under the Terrorism Act and taken to Musgrave Street PSNI custody suite in the city centre, where he was due to be interviewed under caution.
A search at the address in south Belfast has been under way throughout the day.
It comes just a month after Home Secretary Priti Patel said she would consider holding a public inquiry into the bombings.
Ms Patel also wanted to visit Birmingham to meet justice campaigners, including Julie Hambleton, whose 18-year-old sister Maxine died in the bombings.
Responding to news of the arrest Ms Hambleton called it “the most monumental event” in the criminal investigation into the bombings since the quashing of the convictions of the Birmingham Six in 1991.
When she was telephoned by a senior West Midlands Police officer with news of the arrest on Wednesday, she told of how she broke down in tears.
“I couldn’t speak, I was just inconsolable and was just looking at the picture of Maxine,” she said.
“It’s welcome news. It’s overwhelming news.
“It’s tangible progress.”
Ms Hambleton, who is part of campaign group Justice for the 21, said: “It’s something we have been waiting a long time for.
“Having this development – whatever happens – does not in any way lessen our desire for a full public inquiry to be held.
“There are wider issues which need to be examined and so much that went wrong, like why six men were arrested for a crime they didn’t commit.”
Ms Hambleton added: “The fact is we have had to beg and campaign and give up our lives as we knew them to fight for justice.
“Justice that was never facilitated by the authorities whose job it was to do so.
“How was it that for so long, after 21 people were blown up and more than 200 other innocent souls were injured, nobody was looking for the perpetrators?”
James Craig, known as Jimmy, was among those fatally injured in the bombings, with the factory worker and former Birmingham City FC trialist dying of his wounds on December 9 1974.
His 73-year-old brother Bill Craig, an ex-West Midlands Police officer, said he welcomed the arrest, adding there were still “more questions than answers” surrounding the bomb attacks.
Paul Rowlands, whose father John Rowlands was killed in the Mulberry Bush, said: “It’s a positive step.
“It is, however, just a step and it does not detract from the fact that we need a public inquiry.”
John “Cliff” Jones, a postman at New Street station who had survived wounds serving in France and Belgium during the Second World War, died in the Mulberry Bush blast.
Reacting to the arrest, his 72-year-old son George Jones said: “Obviously it’s something positive, and it’s happened just with the anniversary (of the bombings) coming up.
“I hope this time West Midlands Police is more efficient than the original investigation team were.”
In April last year, an inquest jury found a botched IRA warning call led to the deaths of 21 people unlawfully killed in the atrocity.
The two bombs planted in the two pubs also injured up to 220 other victims.
A flawed investigation by West Midlands Police led to the wrongful convictions of the Birmingham Six – one of the worst miscarriages of justice in British legal history.