Metropolitan Police commissioner Dame Cressida Dick accused tech giants on Saturday of making it harder to identify and stop terrorists.
She warned that the heavily relied upon end-to-end messaging encryption feature was making it “impossible in some cases” for the police to do their jobs.
Dick added that advances in communication technologies meant that terrorists were now able to “recruit anyone, anywhere and at any time” through social media and the internet.
The warning came as part of her speech marking the 20th anniversary of the 9/11 attacks.
Available mainly on WhatsApp and Telegram, end-to-end encryption is a privacy feature that makes it impossible for anyone to access and view messages except for the sender and recipient.
While tech giants such as Facebook say that the technology protects the privacy of users, various governments including the US, UK and Australia have repeatedly objected to the idea since 2019, citing fear over the spread of terrorism and extremist ideology.
On Saturday, WhatsApp added another layer of privacy to its messaging process and said that users will soon be able to store end-to-end encrypted backups of their message history on Google Drive on Android or Apple iCloud in iOS.
Until now, messages on WhatsApp were only encrypted as people sent them. Any backups of those messages were left unencrypted.
“We’re adding another layer of privacy and security to WhatsApp: An end-to-end encryption option for the backups people choose to store in Google Drive or iCloud,” said Mark Zuckerberg, CEO of Facebook, which owns the instant messaging giant.
The feature, however, will be optional, and users will be able to avoid it if they wish.
Meanwhile, the UK government is stepping up its efforts to ensure online safety.
Last week, Home Secretary Priti Patel launched a new fund for technologies to keep children safe, titled the Safety Tech Challenge Fund. It reportedly targets child sexual abuse online.