Objective: In February 2009, the Department of Health in England launched the Face, Arm, Speech, and Time (FAST) mass media campaign, to raise public awareness of stroke symptoms and the need for an emergency response. We aimed to evaluate the impact of three consecutive phases of FAST using population-level measures of behaviour in England. Methods: Interrupted time series (May 2007 to February 2011) assessed the impact of the campaign on: access to a national stroke charity's information resources (Stroke Association [SA]); emergency hospital admissions with a primary diagnosis of stroke (Hospital Episode Statistics for England); and thrombolysis activity from centres in England contributing data to the Safe Implementation of Thrombolysis in Stroke UK database. Results: Before the campaign, emergency admissions (and patients admitted via accident and emergency [A&E]) and thrombolysis activity was increasing significantly over time, whereas emergency admissions via general practitioners (GPs) were decreasing significantly. SA webpage views, calls to their helpline and information materials dispatched increased significantly after phase one. Website hits/views, and information materials dispatched decreased after phase one; these outcomes increased significantly during phases two and three. After phase one there were significant increases in overall emergency admissions (505, 95% CI = 75 to 935) and patients admitted via A&E (451, 95% CI = 26 to 875). Significantly fewer monthly emergency admissions via GPs were reported after phase three (219, 95% CI = 229 to 29). Thrombolysis activity per month significantly increased after phases one (3, 95% CI = 1 to 6), and three (3, 95% CI = 1 to 4). Conclusions: Phase one had a statistically significant impact on information seeking behaviour and emergency admissions, with additional impact that may be attributable to subsequent phases on information seeking behaviour, emergency admissions via GPs, and thrombolysis activity. Future campaigns should be a0ccompanied by evaluation of impact on clinical outcomes such as reduced stroke-related morbidity and mortality.