Tokyo: A Tokyo police smartphone app to scare off molesters has become a smash hit in Japan, where women have long run the gauntlet of groping on packed rush-hour trains.

Victims of groping can activate the Digi Police app, which either blasts out a voice shouting “stop it” at top volume, or produces a full-screen SOS message — which victims can show other passengers — reading: “There is a molester. Please help.” The app has been downloaded more than 237,000 times, an “unusually high figure” for a public service app, said police official Keiko Toyamine.

“Thanks to its popularity, the number is increasing by some 10,000 every month,” Toyamine told AFP. Victims are often too scared to call out for help, she said. But by using the SOS message mode, “they can notify other passengers about groping while remaining silent”. There were nearly 900 groping and other harassment cases on Tokyo trains and subways reported in 2017, according to the latest available data from the Tokyo Metropolitan Police Department.