There was something strange about her voice, they thought. It was not unfamiliar but, after a while, it started to go all over the place. Science presenter Liz Bonnin's accent, as regular BBC viewers know, is Irish. But this voice message, ostensibly granting permission to use her likeness in an ad campaign, seemed to place her on the other side of the world. The message, it turns out, was a fake – AI-generated to mimic Bonnin's voice.

I'm about to chat with a dead person. Just last week I saw a particularly disturbing episode of "Black Mirror" in which a devastated widow uploads all of the chats, texts and emails left behind by her husband to a cloud so that she can enjoy his virtual company 24/7. I didn't think my life would catch up with science fiction so soon. I am in bed in my Midtown Manhattan apartment, ambulance sirens blaring on Third Avenue, an iPhone screen glaring in my hand. I pull up the App Store and find Luka, a chat bot program developed and designed by Eugenia Kuyda, whom I used to work with some time ago in Moscow.