Google’s earthquake warning system failed to get to many Turkish residents before February’s deadly tremor, a BBC Newsnight investigation has found.

Google says its alert system can give users up to a minute’s notice on their phones before an earthquake hits.

It says its alert was sent to millions before the first, biggest quake.

However, the BBC visited three cities in the earthquake zone, speaking to hundreds of people, and didn’t find anyone who had received a warning.

The system works on Android phones, essentially any phone that isn’t an iPhone. Android phones, which are often more affordable, make up about 80% of the phones in Turkey.