Edward Snowden has warned people not to use Google’s new chat app, because it lets the company read everything that they say.

Google has finally released its new chat app after showing it off over the summer. It comes with a robot that watches everything people say and then stores it for later analysis, using that data to improve the app itself.

But that also means that chats are stored on Google’s servers indefinitely, and are able to be read by it. The company had initially indicated that the messages would only be stored temporarily, limiting the possible impact of any data breach and retaining some privacy for users.

Google Allo released, letting people chat while being watched by its robots

But it now appears that Google won’t be doing that after all. Instead it will keep hold of all conversations.

Google will use that data to improve parts of the app, such as its smart replies feature. That will allow the app to read through conversations and try and work out how people talk – it can then use that data to suggest what they might want to say to their friends.

But Google would presumably also be able to use that same data at a future date to target ads at users. Since their personal conversations might include some of their most sensitive data, that could lead to prying of a kind that most people would object to.

Making the change does probably keep Google on the right side of the law. By keeping track of all messages, Allo conversations will be accessible by law enforcement with warrants – something that can’t happen on apps like iMessage or WhatsApp, both of which have run into trouble over not being able to give up information to authorities.

All of those problems led Mr Snowden to send out a flurry of tweets telling people not to use Allo.

“Free for download today: Google Mail, Google Maps, and Google Surveillance,” he wrote. “That's #Allo. Don't use Allo.”

Gadget and tech news: In pictures Show all 25 1 /25 Gadget and tech news: In pictures Gadget and tech news: In pictures Gun-toting humanoid robot sent into space Russia has launched a humanoid robot into space on a rocket bound for the International Space Station (ISS). The robot Fedor will spend 10 days aboard the ISS practising skills such as using tools to fix issues onboard. Russia's deputy prime minister Dmitry Rogozin has previously shared videos of Fedor handling and shooting guns at a firing range with deadly accuracy. Dmitry Rogozin/Twitter Gadget and tech news: In pictures Google turns 21 Google celebrates its 21st birthday on September 27. The The search engine was founded in September 1998 by two PhD students, Larry Page and Sergey Brin, in their dormitories at California’s Stanford University. Page and Brin chose the name google as it recalled the mathematic term 'googol', meaning 10 raised to the power of 100 Google Gadget and tech news: In pictures Hexa drone lifts off Chief engineer of LIFT aircraft Balazs Kerulo demonstrates the company's "Hexa" personal drone craft in Lago Vista, Texas on June 3 2019 Reuters Gadget and tech news: In pictures Project Scarlett to succeed Xbox One Microsoft announced Project Scarlett, the successor to the Xbox One, at E3 2019. The company said that the new console will be 4 times as powerful as the Xbox One and is slated for a release date of Christmas 2020 Getty Gadget and tech news: In pictures First new iPod in four years Apple has announced the new iPod Touch, the first new iPod in four years. The device will have the option of adding more storage, up to 256GB Apple Gadget and tech news: In pictures Folding phone may flop Samsung will cancel orders of its Galaxy Fold phone at the end of May if the phone is not then ready for sale. The $2000 folding phone has been found to break easily with review copies being recalled after backlash PA Gadget and tech news: In pictures Charging mat non-starter Apple has cancelled its AirPower wireless charging mat, which was slated as a way to charge numerous apple products at once AFP/Getty Gadget and tech news: In pictures "Super league" India shoots down satellite India has claimed status as part of a "super league" of nations after shooting down a live satellite in a test of new missile technology EPA Gadget and tech news: In pictures 5G incoming 5G wireless internet is expected to launch in 2019, with the potential to reach speeds of 50mb/s Getty Gadget and tech news: In pictures Uber halts driverless testing after death Uber has halted testing of driverless vehicles after a woman was killed by one of their cars in Tempe, Arizona. March 19 2018 Getty Gadget and tech news: In pictures A humanoid robot gestures during a demo at a stall in the Indian Machine Tools Expo, IMTEX/Tooltech 2017 held in Bangalore Getty Gadget and tech news: In pictures A humanoid robot gestures during a demo at a stall in the Indian Machine Tools Expo, IMTEX/Tooltech 2017 held in Bangalore Getty Gadget and tech news: In pictures Engineers test a four-metre-tall humanoid manned robot dubbed Method-2 in a lab of the Hankook Mirae Technology in Gunpo, south of Seoul, South Korea Jung Yeon-Je/AFP/Getty Gadget and tech news: In pictures Engineers test a four-metre-tall humanoid manned robot dubbed Method-2 in a lab of the Hankook Mirae Technology in Gunpo, south of Seoul, South Korea Jung Yeon-Je/AFP/Getty Gadget and tech news: In pictures The giant human-like robot bears a striking resemblance to the military robots starring in the movie 'Avatar' and is claimed as a world first by its creators from a South Korean robotic company Jung Yeon-Je/AFP/Getty Gadget and tech news: In pictures Engineers test a four-metre-tall humanoid manned robot dubbed Method-2 in a lab of the Hankook Mirae Technology in Gunpo, south of Seoul, South Korea Jung Yeon-Je/AFP/Getty Gadget and tech news: In pictures Waseda University's saxophonist robot WAS-5, developed by professor Atsuo Takanishi Rex Gadget and tech news: In pictures Waseda University's saxophonist robot WAS-5, developed by professor Atsuo Takanishi and Kaptain Rock playing one string light saber guitar perform jam session Rex Gadget and tech news: In pictures A test line of a new energy suspension railway resembling the giant panda is seen in Chengdu, Sichuan Province, China Reuters Gadget and tech news: In pictures A test line of a new energy suspension railway, resembling a giant panda, is seen in Chengdu, Sichuan Province, China Reuters Gadget and tech news: In pictures A concept car by Trumpchi from GAC Group is shown at the International Automobile Exhibition in Guangzhou, China Rex Gadget and tech news: In pictures A Mirai fuel cell vehicle by Toyota is displayed at the International Automobile Exhibition in Guangzhou, China Reuters Gadget and tech news: In pictures A visitor tries a Nissan VR experience at the International Automobile Exhibition in Guangzhou, China Reuters Gadget and tech news: In pictures A man looks at an exhibit entitled 'Mimus' a giant industrial robot which has been reprogrammed to interact with humans during a photocall at the new Design Museum in South Kensington, London Getty Gadget and tech news: In pictures A new Israeli Da-Vinci unmanned aerial vehicle manufactured by Elbit Systems is displayed during the 4th International conference on Home Land Security and Cyber in the Israeli coastal city of Tel Aviv Getty

Another read: “What is #Allo? A Google app that records every message you ever send and makes it available to police upon request.”

Google does allow people to switch into a different mode, called Incognito, where conversations will be end-to-end encrypted so that they can’t be read by Google. But that isn’t turned on by default and leads most of the app’s features to break, turning it into just a conventional chat app.

"We've given users transparency and control over their data in Google Allo," said a Google spokesperson. "And our approach is simple – your chat history is saved for you until you choose to delete it. You can delete single messages or entire conversations in Allo.