CHILDREN OF THE DAMNED by A.V.Sellwood A Four Square book published by Nel 1964
Adapted from the film of the same name , running 128 pages - this fits the Nel format perfectly. The film for those unaware is the sequel to VILLAGE OF THE DAMNED ( based on John Wyndham's MIDWICH CUCKOOS). In the sequel six children of different nationality exhibit mental powers far beyond a normal intelligent adult. Politicians and scientists struggle to understand as the children of the damned hide in an abandoned church.
Thanks for the scan, K.C. This one has been on my hit list for yonks, not just 'cause i rate the film (truly creepy) but because A. V. Sellwood collaborated with Peter Haining on his first published book, the superlative Devil Worship In Britain!
From the first, I set myself against "literature"; the story was the thing, and no amount of style could persuade me to select a story that lacked genuine, unadulterated horror. For those who wanted something high-brow there was plenty.