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The London Westminster attack perpetrated by Khalid Masood must be a “wake-up call” for technology giants over their efforts to tackle terrorist content online, the acting head of Scotland Yard has warned.

Craig Mackey delivered a stark message to platforms which have come under fire for hosting extremist material, calling on them to grasp what it means to “put your own house in order”.

According to, Facebook, Google and Twitter are among firms that have repeatedly faced calls to do more to detect and remove jihadist and other extreme videos and web pages.

Appearing at the London Assembly’s Police and Crime Committee, Mackey, the acting commissioner of the Metropolitan Police, said: “If you are going to have ethical statements and talk about operating in an ethical way it actually has to mean something.”

The debate flared up after it emerged that information on how to mount an attack was easily accessible online.

A furore over security services’ access to terrorists’ communications erupted following reports that Khalid Masood’s phone connected with encrypted messaging service WhatsApp just before the attack.

Mr Mackey said investigators are examining an “enormous” volume of digital information, including some in “secure applications”.

He said: “We work hard with the industry to highlight some of the challenges of these very secure applications.

“It’s a challenge when you are dealing with companies that are global by their very nature because they don’t always operate under the same legal framework as us.”

WhatsApp has said it is “co-operating with law enforcement as they continue their investigations”.

Detectives believe Masood acted alone in executing the attack but are continuing to investigate whether anyone else was involved in any way.