In 1952, the worst smog in living memory descended over London, reducing visibility so badly that people could barely see a metre in front of them. Public transport came to a standstill, cinemas and theatres closed, and the weekend's football matches were cancelled. The pollution also caused the early deaths of around 5,000 Londoners and finally forced the government to tackle pollution. Witness speaks to Rosemary Merritt, whose father died in the smog. PHOTO: Getty Images.