The United Kingdom (UK) ratified Framework Convention on Tobacco Control (FCTC) on December 16, 2004. In 2002, a team of researchers from Australia, Canada, the United Kingdom, and the United States launched the flagship ITC Four Country (4C) Survey. Ten survey waves of ITC 4C Survey have been conducted among a cohort of adult smokers aged 18 and older in the UK. In 2003, the UK (Waves 1-4) along with Ireland (Waves 1-3) established another cohort to measure smoke-free regulations and this cohort was joined by Scotland in the last two waves of the UK-Ireland cohort. . In 2016, the team expanded the cigarette smoking 4C survey into the ITC Four Country Smoking and Vaping Survey, to investigate the relationship between nicotine vaping products (NVPs) and/or heated tobacco products (HTPs) and cigarette smoking among adult smokers, recent former smokers, vapers, and HTP users in Australia, Canada, England, and the United States, and to inform emerging policies related to NVPs and/or HTPs. These four countries have similar cigarette-smoking rates, but divergent policies on vaping product/HTP use.