Parents of twins with autism so severe they were forced to contain them in a prison-like home have gone to great lengths to improve their behaviour. As Mark and Annie Montague walk arm in arm along the beach, with their 11-year-old twins chasing waves in and out of shore, they are the image of a perfect family. But their home in nearby Graveney, Kent tells a more complicated story. In this idyllic village, a detached ramshackle house stands surrounded by high fence posts and chicken wire. Inside, doors are bolted shut, telephones are hidden in locked wooden boxes metres from the ground and barring a table, few chairs and a sofa there is no furniture. No carpets line the floors and a lone painting is tightly screwed in place. This has been a way of life for the Montagues since their twins, Samuel and Jacob, 11, were diagnosed with severe autism when they were just two-years-old.