The UK Government demanded that WhatsApp comes up with a way to offer access to encrypted messages this summer, Sky News has learned - a request that was rejected by the instant messaging service.

The inability to access terrorists' encrypted conversations is creating a "black hole" for security services, according to a security source.

Terrorists are "frequent users of encrypted apps" - specifically WhatsApp and Telegram, the source said.

"It is crucially important that we can access their communications - and when we can't, it can provide a black hole for investigators," the source added.

At a United Nations discussion on Wednesday, the Prime Minister Theresa May will ask technology companies to do more to help governments fight terrorism in the wake of the explosion at Parsons Green Tube station.


Encrypted messaging apps were used ahead of the attacks on Westminster, Manchester and London Bridge.

The devices of one of the Parsons Green suspects have been recovered and are being investigated by intelligence agencies.

What the tech companies say about encryption

Apps such as WhatsApp, Telegram and Apple iMessage employ end-to-end encryption. Messages sent by users are scrambled by a code contained on the app on their phone, or the phone itself.

The systems are designed so that tech companies themselves do not have access to the content of a message.

Sky News understands that WhatsApp co-operates with law enforcement to provide the metadata it does hold - the name of an account, when it was created, the last seen date, the IP address and associated email address.

WhatsApp says it "appreciates the work that law enforcement agencies do to keep people safe around the world. We are prepared to carefully review, validate and respond to law enforcement requests based on applicable law and policy".

But the company argues that it can't provide data that WhatsApp itself does not collect in the first place, including the contents of a message.

In a statement on its website, the company writes: "Naturally, people have asked what end-to-end encryption means for the work of law enforcement. WhatsApp appreciates the work that law enforcement agencies do to keep people safe around the world.

"We carefully review, validate, and respond to law enforcement requests based on applicable law and policy, and we prioritise responses to emergency requests."

Raffaello Pantucci, director of security at the Royal United Services Institute, told Sky News: "The way you have to think that the terrorist groups use these sorts of applications is the same way that all of us use encrypted applications, which is to plan our lives.

"So what you're increasingly seeing is that individuals are forming relationships or advancing relationships using these online communication methods.

"And they're using this to direct plots. We've had some instances where you've had individuals based in Raqqa who are steering people to launch terrorist attacks from a distance and are communicating with them blow by blow using these encrypted communications.'"

Image: The Westminster attacker used WhatsApp moments before the atrocity began

Sky News understands that 80% of investigations into terrorism and serious crime are now impacted by encryption.

Terrorists themselves are now "far more cyber savvy" than they have been before, the security source told Sky News.

At a meeting this summer, British officials asked WhatsApp to come up with technical solutions to allow them to access the content of messages - effectively, a back door.

Cybersecurity experts say that creating a back door for a government would weaken encryption for everyone, as it would be a prime target for hackers.

But UK intelligence officials believe a compromise could be possible - pointing out that cybersecurity isn't binary and that services offer different levels of cybersecurity to deal with different levels of threats.

The UK Government remains firm in its aspiration to obtain the unencrypted content of messages under a proper warrant.

The problem of obtaining access to the content of communications is larger than any one company.

March: Rudd calls for access to WhatsApp data

Telegram remains popular for dissemination of jihadist materials. Sky News observed channels - including al Qaeda's official mouthpiece and Abu Qatada, the radical cleric deported to Jordan - pumping out propaganda.

Recruiters pump out content to lure the curious. That can inspire attacks - or they can go one further and use the same app to direct attacks a continent away.

Telegram told Sky News it has a dedicated channel to remove terrorist accounts, explaining: "As a result, jihadi channels usually go down within a few hours, long before they can reach any traction."

Earlier this year, Facebook, YouTube, Twitter and Microsoft - along with other tech companies - announced they would form the Global Internet Forum to Counter Terrorism in an attempt to tackle extremism on their platforms.