But the Fold and Huawei’s Mate X are folding devices and this alleged TCL design is the first of its kind. CNET said a “working prototype” was due to be exhibited at the cancelled Mobile World Congress trade show. 

The leak may well start off a month or so of official and unofficial unveilings of what the world’s largest phone show would have brought. This one is probably just a concept device, though.

The unnamed phone looks like it functions at a regular smartphone size before a sliding panel is pulled from behind and to the left to turn the device into something with double the screen size. It’s unclear how this would work but appears as though there is no physical split to the screen.

The most likely way it functions is with a wraparound plastic screen that unfurls as you pull out the sliding section.

From the back the phone bears a resemblance to the Huawei Mate X with the camera array, as well as  TCL’s own 10 Pro smartphone

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Henry is Tech Advisor’s Phones Editor, ensuring he and the team covers and reviews every smartphone worth knowing about for readers and viewers all over the world. He spends a lot of time moving between different handsets and shouting at WhatsApp to support multiple devices at once.