Long Lost Family: Born Without Trace (ITV1)Rating: Four out of five starsAt Waterloo station four years after the Second World War, an unmarried mother left a bundle of cloth on a carriage seat and slipped off the train unseen — leaving behind nothing to identify herself. Though doctors thought she must be about five weeks old, the baby girl weighed barely 5lb. Long Lost Family: Born Without Trace makes fascinating use of current technology to achieve the impossible, winding back time to discover information that seemed lost forever. With the series now in its seventh year, we've seen this done repeatedly, but it never loses its capacity to astound and move us. In far less than another lifetime, shows like Long Lost Family will be redundant, I suspect.