ObjectivesTo investigate opposition to standardised tobacco packaging in the UK. To increase understanding of how transnational corporations are adapting to changes in their access to policymakers precipitated by Article 5.3 of the Framework Convention on Tobacco Control (FCTC).DesignCase study web-based documentary analysis, using NVivo V.10. Examination of relationships between opponents of standardised packaging and transnational tobacco companies (TTCs) and of the volume, nature, transparency and timing of their activities.SettingUK standardised packaging policy debate 2011–2013.ParticipantsOrganisations selected on basis of opposition to, or facilitation thereof, standardised tobacco packaging in the UK; 422 associated documents.ResultsExcluding tobacco manufacturing and packaging companies (n=12), 109 organisations were involved in opposing standardised packaging, 82 (75%) of which had a financial relationship with 1 or more TTC. These 82 organisations (43 actively opposing the measure, 39 facilitating opposition) were responsible for 60% of the 404 activities identified, including the majority of public communications and research production. TTCs were directly responsible for 28% of total activities, predominantly direct lobbying, but also financially underwrote third party research, communication, mass recruitment and lobbying. Active organisations rarely reported any financial relationship with TTCs when undertaking opposition activities.ConclusionsThe multifaceted opposition to standardised packaging was primarily undertaken by third parties with financial relationships with major tobacco manufacturers. Low levels of transparency regarding these links created a misleading impression of diverse and widespread opposition. Countries should strengthen implementation of Article 5.3 of the FCTC by systematically requiring conflict of interest declarations from all organisations participating in political or media debates on tobacco control.