The NSPCC, a charity campaigning for child protection in the UK, has written to the app's developer, Niantic, asking for a safety overhaul. Peter Wanless, chief executive for the NSPCC, says the app "appears susceptible to being hijacked by users who wish to harm other players." He points to a number of high-profile news reports, including one that suggests Pokémon Go players have been led to a sex shop in Plymouth, England.

Technically, the app isn't available in the UK, although countless players have side-stepped the problem by changing their app store location or downloading an Android APK. Before it officially crosses the pond, Wanless says Niantic should be looking at the game and changing how it plays.

"Given Pokémon's already massive popularity with children, the NSPCC is concerned that basic safety standards appear to have been overlooked. I urge you to urgently reassess your app and its security and safety features. We all have a responsibility to ensure that children are protected and as creators of a game with substantive reach, you have a weighty responsibility to protect your young users."

Specifically, the NSPCC wants "security and reporting functions" inside the app. It stops short of explaining just how these would operate -- but it's safe to assume that users, parents included, would be able to flag specific areas that they deem inappropriate. Niantic would then review them and, if it agreed with the report, delist the location or tag it as dangerous.

"All too often we see examples of companies simply not doing enough to protect children – their safety is an afterthought," he presses. "This cannot go on – children live in a digital age, it is a standard feature of their lives. Therefore, their welfare must be a standard consideration when developing products that companies know children will use."

The NSPCC says it would be happy to work with Niantic and The Pokémon Company before the app is released in the UK. We've asked both companies to comment on the letter and will publish their responses.