The 66-year old, referred to as Lance Corporal J in the 2010 Saville Report into Bloody Sunday, was arrested in Co Antrim by detectives from the PSNI’s Legacy Investigation Branch and taken to a police station in Belfast to be interviewed.

He is the first person to be arrested in connection with the controversial incident in Londonderry on 30 January 1972, which led to the death of fourteen civilians.

Detective Chief Inspector Ian Harrison, leading the investigation, said the arrest “marked a new phase in the overall investigation which would continue for some time”.

Peter Madden of Madden & Finucane Solicitors, who represent most of the victims’ families, welcomed the arrest.

He said: “This is a very welcome development. Following the publication of the Saville Report we made extensive submissions to the Police and Public Prosecution Service concerning the overwhelming evidence of joint enterprise between Soldiers P and J in relation to the murders of John Young and Michael McDaid.

“In the event that criminal charges follow, those charged must face public trial and will lose their anonymity.”

A spokesperson for the Ministry of Defence (MOD) said: “We are aware an ex-soldier has been arrested by the Police Service of Northern Ireland in connection with their investigation into the events of Bloody Sunday.

“It would be inappropriate to comment further on an ongoing criminal investigation at this stage.”