In 2024, for the first time since national records began, more adults in Great Britain used e-cigarettes than smoked tobacco cigarettes [1]. Data released by the UK Office for National Statistics in November 2025 showed that 10.0% of adults aged 16 years and over were current e-cigarette users, compared with 9.1% who smoked tobacco (See Figure 1). This statistical crossover is a notable milestone in tobacco control, occurring alongside sustained declines in smoking prevalence—from 20.2% in 2011 to 10.6% in 2024. While cross-sectional and temporal data limit causal inference, these trends are consistent with harm reduction approaches operating alongside traditional tobacco control measures in driving population-level declines in smoking.