An administrative blunder could have stopped security services from linking two of the London Bridge terrorists before they carried out their attack, an MI5 officer has said.
A request for intelligence from Italian authorities into Youssef Zaghba had not been actioned, a senior officer identified only as Witness L told the Old Bailey.
A serious crime alert was put out on Zaghba after he was stopped when trying to fly from Bologna to Istanbul in March 2016.
When asked why he was travelling, he replied, “to be a terrorist” before correcting himself to “tourist”, the inquest into the London Bridge attack heard.
Italian officials had approached MI5 in April that year with a series of questions relating to Zaghba but no action was taken and it wasn’t recorded on the system, Witness L, giving evidence from behind a screen, told the court.
Asked why MI5 did not take any action too, he said: “Because the request, which was a request for tracing of the type we discussed the other day, went to an incorrect addressee.”
The witness, who is head of policy strategy and capability in MI5’s international counter-terrorism branch, added: “It went to the wrong MI5 addressee. I can find nowhere it was filed within the MI5 records.
“I suspect this was probably a misunderstanding. I suspect the individual to whom it was sent did not understand they needed to take any action at all.
“No response was given to the Italian authorities as far as I am aware.”
When asked if the “administrative errors” had deprived security services of the opportunity of linking Zaghba to fellow attacker Khuram Butt, Witness L said: “Yes, it is possible.”
He added: “So I think this is an interesting and inevitably speculative chain of events.
“Had we been interested, I suspect our first response would have been to return to the Italian authorities and to ask for more detail, because the information provided, namely that he’d arrived at an airport and said he was a terrorist, and then changed it to tourist, is unusual.
“So our first step would have been to ask the Italians for more information.
“Had they provided information of interest, I think it is possible we would consider putting him on a terrorist watch list in addition to the existing serious crime watch list.”
Witness L said that an investigation into Zaghba would have been “unlikely” and added: “So I think active investigation would have been unlikely, but flagging as a person of interest, particularly as they came in and out of the UK border, feels more likely.”
Butt, 27, Zaghba, 22, and Rachid Redouane, 30, killed eight people and injured 48 more in a van and knife attack on 3 June 2017.
The pair mowed down pedestrians on London Bridge and then stabbed innocent bystanders in nearby Borough Market.
Xavier Thomas, 45, Christine Archibald, 30, Sara Zelenak, 21, Sebastien Belanger, 36, James McMullan, 32, Kirsty Boden, 28, Alexandre Pigeard, 26, and Ignacio Echeverria, 39, were all killed.
The inquest continues.