It began as a family day out for Jess Finnegan and there hadn't been too many of them recently. She and Mickey had only met about a year ago, fallen in lust with each other - and then Jess became pregnant. They married just two months before the baby was due, but only four weeks before Louis was born. The day out at the exhibition at the Tate Modern was a treat and a break from the routine demands of motherhood. It turned into a nightmare.