Design—A prospective, controlled trial was conducted in four TV regions in central and northern England. One region received no intervention (controls), two regions received TV anti-smoking adver- tising (TV media), and one region received TV anti-smoking advertising plus locally organised anti-tobacco cam- paigning (TV media + LTCN). The TV advertisements were screened in two phases over 18 months; during the first phase the intensity of the advertising was varied between TV regions. 5468 men and women (2997 smokers, 2471 ex-smokers) were selected by two stage random sampling and interviewed before the intervention, of whom 3610 were re- interviewed six months later, after the first phase of the campaign. Only those interviewed at six months were followed to the main end point at 18 months when 2381 subjects were re-interviewed.