At 18 months, Joe's behaviour deteriorated; he would line up all his toys around himself as he withdrew into his own world, and started kicking Sarah. 'I would grab him and feel the need rising up to shake him,' she says. 'I'd have to put him down, go into another room for 10 minutes and shut the door to keep him safe. I'd hear him screaming on the other side. I'd return out of a sense of duty rather than love. My husband only saw the tip of the iceberg; he now admits he withdrew into his work as a police officer by taking longer shifts.' Sarah put Joe's behaviour down to her failing. (It was not until he was six that a diagnosis of autism was made.) 'I felt I had no control over him and even called my husband home from work a couple of times because I didn't trust myself and was worried I'd hurt him.' When Joe was two, Sarah gave birth to Lola, who seemed to underline the problems between son and mother. 'Lola was sheer bliss and radiated peace. I bonded with her instantly. I felt such guilt about that.'