Participants

Participants were recruited from 25 January to 1 February 2019. The trial ended when we had reached the number of responses determined by our power calculations. We recruited participants via a number of third‐party panel providers, who have access to a pool of people who have given their consent to be contacted in order to answer on‐line questionnaires. Participants were paid a fixed fee of approximately £1 for their time.

Participants were required to be English, aged over 18 years and report drinking alcohol, as measured by the first question of the Alcohol Use Disorders Identification Test (AUDIT‐C) questionnaire [23] (see Procedure for full details of the screening). We specified that the sample should be representative of the adult population of England in terms of age, gender and region in which it was (see Supporting information, Table A1, Appendix S2).