Downgrading risk of Westminster attacker '˜a sound decision', says MI5 officer

Police officers were placed on high alert following the attack.

Giving evidence amid tight security at the inquest into the victims’ deaths, the officer identified as Witness L said the atrocity could not have been stopped.

“There simply wasn’t enough intelligence for us to work on that would have allowed us to identify his plot and work with the police to frustrate it,” he said.

Shielded from the court by a green curtain, and with no one other than lawyers and court transcription staff allowed to use phones and computers during his evidence, he told the Old Bailey: “Masood engaged in attack planning on his own. It’s very difficult to make a decision as to when he decided to mount the attack.”

The court heard how Masood came to the attention of MI5 in 2004, when his number was found in the phone of Waheed Mahmood, one of a group of terrorists who plotted to plant fertiliser bombs.

He also had contact on a number of occasions between 2004 and 2009 with another suspect under investigation by MI5. The suspect had his address, email addresses and phone numbers.

In February 2010 there was a “vague and uncorroborated” report of someone called Khalid Masood - “an extremist based in Saudi Arabia” - helping a UK terror cell plan to travel to Pakistan to receive training from al Qaida.

He was initially classed as someone who posed a threat to national security, but was downgraded to someone who may pose a threat the following month, when MI5 investigators discovered Masood was not involved.

In December that year a review found that as Masood was not involved in facilitating travel or in any other aspect of the plot, he could be downgraded again.

Witness L told the Old Bailey: “He was downgraded to a target who was not considered to be a risk to national security.”

No record was made at the time of the reasons why the decision was taken.

Counsel to the inquest Jonathan Hough QC read from a written statement by Witness L that said: “We have reviewed the decision to close Masood (as a person of interest) with the benefit of hindsight and we conclude the decision was sound.”

The officer went on: “It was logical, necessary and proportionate to consider him a closure.”