This was a children’s novel about a advanced human society living separate to an abandoned post-disaster world.

The inhabitants now live in a peaceful and educated way, having somehow atoned for the previous mistakes. Everyone wears a bodysuit that changes colour dependant on the mood of the wearer. One scene describes a young girl’s family living room where the children ‘paint’ an image on a kind of computer screen that is displayed as an artwork.

In another, the children visit the old city, a chaotic abandoned world. My memories are sketchy but I think they find something there and the protagonist – I think it was the young girl – must walk through a super modern hall, a busy public area, with her bodysuit flashing colours wildly. The bodysuits glowed gently when the wearers were calm, and most were calm, so it was obvious to all when one was upset or aggressive.

Really quite incredibly prophetic as it must have been written before 1985. I borrowed it from a library in Australia in the early 1980’s.