Ok, I confess. I can't always spot an embryonic superstar. I used to see Miranda Hart's shows at the Edinburgh Festival every year and while I always giggled I dismissed her performances as self-conscious, galumphing, knockabout fluff. One year I was due to review her show – a spoof chat show, I think – and it was cancelled at the last minute. An indication of either how haphazard she was or what a perfectionist she was and she didn't want to put something under par above the parapet.