The internet has brought a surge in pornographic websites — most lawful, but a growing minority illegal. Accessing them has drawn ordinary, law-abiding people into criminal proceedings, sometimes wrongly. Shut one illegal site down and another opens almost immediately. The National Crime Agency and UK police actively pursue this. Operation Notarise (2014–15) identified over 25,000 people via covert tracking of illegal image-sharing, leading to 745 arrests.