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?”