Bad cough is lung cancer's main symptom, highlights campaign It is Britain's most lethal cancer but most people do not know the principal symptom that may indicate its presence. While there is wide awareness that a breast lump is a warning sign of breast cancer and that bleeding could indicate bowel, kidney or bladder cancer, only one in ten people knows that a persistent cough could point to lung cancer. Tomorrow the Be Clear on Cancer campaign launched with adverts on TV, radio, print and online will urge anyone who has had a cough for more than three weeks to visit their doctor. The Government campaign is supported by celebrities including comedian Ricky Gervais and Manchester United manager Alex Ferguson who will be pictured holding x-rays of healthy lungs. Care Services Minister Paul Burstow said: "Lung cancer is the biggest cancer killer in this country but worryingly many people don't know the signs and symptoms that could save their lives. The earlier lung cancer is diagnosed, the better the chance of survival. The message from this campaign is simple; if you have a persistent cough for three weeks or more, visit your GP. The danger of a persistent cough is less appreciated than the change in the appearance of a mole on the skin which is known by 25 per cent of people to be a warning sign of skin cancer, according to a survey by Cancer Research UK in 2010. Lung cancer affects 41,000 people every year in the UK , most over the age of 55, and causes 34,000 deaths. Cases have been declining in men, as a result of the decline in smoking that started in the 1950s and 1960s, but are still rising in women who took up smoking later. It takes around 30 years for lung cancer to develop. When diagnosed at its earliest stage, as many as 80 per cent of people are alive five years after diagnosis compared with only 7 per cent diagnosed at a late stage. Professor Sir Mike Richards, National Cancer Director for England, said: It is vital that cancer patients get treated quickly so they have the best chance of surviving. We have made early diagnosis central to our Cancer Outcomes Strategy. Earlier diagnosis of Lung Cancer combined with the best treatments could help save an additional 1,300 lives a year. British actor and comedian, Ricky Gervais, whose mother died of lung cancer at the age of 74, said: It's devastating when you see someone you love dying from lung cancer. It's a horrible, horrible disease. My mother's death was very sudden and you can't help wondering if things would have been different had it been spotted earlier. If you've had a bad cough for three weeks and you can't get rid of it, just make an appointment with your GP today. Paula Chadwick, chief executive of the Roy Castle Lung Cancer Foundation, said: "We really hope people will begin to associate a persistent cough as a symptom of lung cancer, the way they associate a lump as a symptom of breast or testicular cancer. The reality is it probably will be just a cough but if it is something more serious, getting it diagnosed early could just save your life.