BACKGROUND: A now extensive literature has documented political strategies of health-harming industries (HHIs), but little is known about their engagement with parliamentary select committees. Recent investments by trans-national tobacco corporations (TTCs) in electronic nicotine delivery systems (ENDS) has raised concerns that industry actors may be using these to re-engage policy-makers in ways precluded by the Framework Convention on Tobacco Control (FCTC) Article 5.3. METHODS: This article examines tobacco industry engagement with the United Kingdom House of Commons Science and Technology Committee (STC) inquiry into e-cigarettes. It draws on a qualitative analysis of semi-structured interviews with committee members and support staff (n=4) triangulated against written and oral evidence submissions. RESULTS: TTCs featured prominently in the STC inquiry via written and oral submissions. Opportunities existed for industry engagement, and potential influence, at each stage of the process. There was an absence of oral testimony from those sceptical about the potential health benefits of ENDS. The governance mechanisms in place for select committees appear inadequate for protecting committee work from industry influence. As it relates to TTCs, this has implications for the UK's commitments under FCTC Article 5.3, yet understanding of the FCTC and the requirements of Article 5.3 compliance within the committee were limited. CONCLUSION: The governance of select committees requires urgent reform in order to balance norms of openness and participation with the need to protect their work from power of economic actors with conflicts of interest (COI). This is particularly the case in relation to TTCs and adherence to FCTC Article 5.3. These findings are of relevance to other select committees whose work affects the interests of HHIs. Further research is needed on other committees and sectors.