"The tale of the Gibbons girls is one of sibling rivalry that seemed in danger of turning murderous, featuring a baffling childhood pact of silence that propelled them, via educational exclusion, to become teenage outcasts who responded to dashed literary ambitions and bungled sexual adventures with a life of petty crime that would lead them ultimately to Broadmoor Psychiatirc Hospital.
Jennifer, born 10 minutes after June, imagined her older sister to be cleverer, prettier, more beloved. Jennifer feared she would be left behind. Later, June would write of Jennifer: 'She wants us to be equal. There is a murderous gleam in her eye. Dear lord, I am scared of her. She is not normal ... someone is driving her insane. It is me'.
Anne Treherne, an expert on elective mutes, met the twins and became convinced a game was going on: that by secret eye signals Jennifer was stopping June speaking, controlling her as if she were a robot. The twins spooked her colleagues: moving extremely slowly in perfect time, they seemed inhuman, like 'zombies', drinking cups of tea or taking off their coats in eerie unity. A head teacher even called Jennifer 'evil'...."
Twins from Kubrick's The Shining, above.