In April 2002, Hewson was one of the leaders of an effort which delivered over a million postcards demanding that the facility be shut down; recipients included British Prime Minister Tony Blair, Prince Charles, and Norman Askew, head of British Nuclear Fuels Limited. (The message to the first said, "Tony, look me in the eye and tell me I'm safe.") She personally delivered a giant postcard to Blair at 10 Downing Street. The Shut Sellafield Campaign had its postcards stocked in Superquinn and Dunnes Stores supermarkets, and Hewson publicly engaged Tesco when they refused to do the same. The campaign was backed by celebrities, including Ronan Keating and Samantha Mumba, and Hewson made many newspaper and radio appearances on its behalf. It was the first prolonged exposure Hewson had to the public eye, after two decades of mostly being focused upon maintaining her privacy. Her continued activism also meant that she too would not always be around for the couple's children.