PROGRESS described as “immense” has been made in the investigation into the Manchester bombing, with police saying they are confident “key players” have been arrested.

The UK’s top counter-terrorism officer, Mark Rowley, said “significant” arrests and “finds” had been made with a “large part of the network” uncovered.

“They are very significant, these arrests,” he said. “But there’s still a little bit more to do.”

Eight suspects aged between 18 and 38 are now in custody. It has also been revealed that 12,000 people have previously been watched by counter-terrorism agencies in addition to the 3000 currently being monitored as part of 500 live investigations.

The eight in custody are the bomber’s brother, 24-year-old Ismail Abedi, who was arrested in Whalley Range, south Manchester, on Tuesday; males aged 18, 21 and 24 arrested in the Fallowfield area of the city on Wednesday; a 33-year-old man who was carrying a suspicious package arrested in Wigan on Wednesday; a 22-year-old man arrested in Nuneaton at gunpoint by counter-terror officers on Wednesday; a 38-year-old man picked up in Blackley, north-east Manchester, on Thursday; and a 30-year-old man held in the early hours of yesterday morning in Moss Side, south Manchester.

A woman of 34 arrested in Blackley on Wednesday and a 16-year-old male arrested in Withington on Thursday have been released without charge.

Speaking after chairing a meeting of a UK Government emergency Cobra committee, Home Secretary Amber Rudd said the Joint Terrorism Analysis Centre had assessed the terror threat level should stay at critical while the “live” police operation is continuing.