In the early Seventies, the industry came up with another clever scheme: “light” or “low-tar” cigarettes that had tiny, laser-cut holes in their paper and would, in theory, dilute the smoke with fresh air, and thus reduce its harmful toxins. Once again, there was a problem: “Filter ventilation is probably the greatest fraud that has ever been perpetrated on consumers,” Zeller says. “All of the patents for this technology said that the holes were put 12mm from the mouth end of the cigarette. Why? Because when you place that cigarette in a smoking machine, which is used to measure tar and nicotine delivery, the ventilation holes are left open and that has a dilution effect. But when a human being smokes that cigarette, 12mm is where your lips and fingers go. So they block the holes.” A 1980 study found that when these holes are blocked, the toxic load of a “low tar” or “light” cigarette can be increased by up to 300 per cent.