--- - |2 Abstract We draw on findings from qualitative interviews with health data researchers, GPs and citizens who opted out from NHS England's care.data programme to explore controversies and negotiations around data sharing in the NHS. Drawing on theoretical perspectives from science and technology studies, we show that the new socio‐technical, ethical and economic arrangements were resisted not only on the basis of individual autonomy and protection from exploitation, but also as a collective effort to protect NHS services and patient data. We argue that the resulting opt‐outs were a call for more personal control over data use. This was not because these citizens placed their personal interests above those of society. It was because they resisted proposed arrangements by networks of stakeholders, not seen as legitimate, to control flows and benefits of NHS patient data. Approaching informed consent this way helps us to explore resistance as a collective action for influencing the direction of such big data programmes towards the preservation of public access to healthcare as well as the distribution of ethical decision‐making between independent, trustworthy institutions and individual citizens. - 'Sociology of Health &Illness, EarlyView. '