Poison pen letter writers be warned - these post boxes have eyes.
Post boxes around south London have been given a set of eyes thanks to a mysterious graffiti artist.
A number of the stickers have emerged in previous months, and it's proving a hit with residents.
Pictured are examples found in Sutton and Wandsworth.
Although Royal Mail could see it as an eyesore, Mark Bielecki, who works in Sutton found it hilarious.
he said: "It's brilliant. I've seen them in a few places now and the post boxes actually look happy. Does anyone know The Phantom Sticker?"
The phenomenon does not appear to be a new one, post boxes as far afield as Canada have been seen with a pair of stuck on eyes.
Have you seen the stickers? Contact firstname.lastname@example.org