A 65-year-old man is continuing to be held in the North in connection with the murders of 21 people in the 1974 Birmingham pub bombings.
The arrest came just days before the 46th anniversary of the two deadly November 21st blasts which ripped apart the Mulberry Bush and Tavern in the Town pubs.
The man was arrested in Belfast yesterday morning by officers from West Midlands Police assisted by the Police Service of Northern Ireland (PSNI).
He was arrested under the Terrorism Act and taken to Musgrave Street PSNI custody block in the city, while searches continued at his address throughout the day.
The force said he would be interviewed under caution at a police station in Northern Ireland.
Officers have an initial 48 hours to question a suspect under the Act, police said today.
At an inquest into the bombings last year, a jury concluded a botched IRA warning call on the night led to 21 people being unlawfully killed.
The bungled West Midlands Police inquiry in the immediate aftermath of the bombings led to the wrongful convictions of the Birmingham Six, one of the worst miscarriages of justice in legal history.
They were later freed in 1991 after their convictions were quashed.
'Overwhelming news'
During evidence given at last year’s inquest, an anonymous IRA volunteer, identified at the hearing only as 'Witness O', named the men he said had been involved in the attacks.
Yesterday's arrest has come a month after Home Secretary Priti Patel said she would consider holding a public inquiry into the bombings.
Ms Patel also said she wants to visit Birmingham to meet justice campaigners, including Julie Hambleton, whose 18-year-old sister Maxine died in the bombings.
Reacting to news of the arrest – the first in four decades in connection with the bombings – Ms Hambleton, who is part of the victims’ families’ campaign group Justice 4 the 21, called it “monumental”.
She broke down in tears when telephoned by a police officer with the news.
“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.”