Introduction: We have undertaken four online surveys of Stop Smoking Service (SSS) practitioners in England, between 2011 and 2016, in order to enhance our understanding of e-cigarettes: a fast moving new phenomenon. It is important to understand whether e-cigarettes can ameliorate or exacerbate health inequalities given that smoking is one of the most serious causes of excessive mortality and morbidity among disadvantaged groups globally. Aims: To update findings of previous surveys and examine socioeconomic status differences in e-cigarette use and efficacy. Methods: Analysis was undertaken of electronic surveys, particularly, the most recent 2016 survey (n = 514) and 2015/16 SSS client routine monitoring data. Results: SSS practitioners were becoming more positive about e-cigarettes: 42% agreed that e-cigarettes were a good thing compared with 15% in 2011. Reported use of e-cigarettes among SSS clients was low (about 3%) despite higher quit rates (63% of clients reported being quit at four week follow-up, compared with 51% overall). Where socioeconomic differences in e-cigarettes' efficacy for quitting were identified, affluent and working smokers were advantaged. Conclusions: Low use of e-cigarettes by clients and practitioner opinions suggest that further education of SSS staff is needed if they are to adopt the current service recommendations about e-cigarettes.