Evan Spiegel refuses to be scared of Facebook. Confidence helped the 27-year-old Snap chief executive take a photo messaging app from a Stanford University coursework project to an almost $20bn initial public offering. The threat of Facebook has been following all the way.

In 2013, when the company behind Snapchat was just two years old, its co-founder (his partner was a fellow student, Bobby Murphy) was quizzed on stage about Poke, Facebook’s first attempt at imitating the app’s photo messaging. “Certainly it is scary when a giant enters your space and you are a small company,” Mr Spiegel said at the TechCrunch Disrupt conference. He laughed it off: Poke failed, and that became the “greatest Christmas present we ever had”.

But the world’s largest social network does not give up and has relentlessly imitated Snapchat since Mr Spiegel turned down its $3bn acquisition offer in 2013. Earlier this year, just as Snap headed for the public markets, Facebook finally succeeded in popularising a version of “Stories” in four of its apps — the Snapchat feature that expires after 24 hours.