In Study 2 of this project, we examined the effect of including a proscriptive versus prescriptive injunction with information about UK government COVID-19 behavioral rules and guidance on intentions to comply with government guidelines, and examined perceived legitimacy of advice as a moderator, in a national sample representative of age and gender. The results of Study 2 showed that perceived legitimacy moderated the effect of Injunction Type both on intentions to comply with UK government COVID-19 guidelines. Significant contrasts showed that when perceived legitimacy was low, participants who were exposed to the proscriptive injunction reported lower intentions to comply with UK government COVID-19 guidelines compared to participants who were exposed to the prescriptive injunction condition. The findings have implications for the design of public health information.