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Background The effects of daylight saving time (DST) clock changes on health are the subject of intense policy debate. Many countries, including the US and those in the EU, are moving to abolish the transitions. However, the current literature is fairly mixed. Furthermore, few studies have looked at the effect on the health system as a whole and evidence from England is scarce. We aimed to explore the effects of the DST transitions on a range of health events in a large dataset of linked English primary and secondary care records.Methods We used primary care records from the Clinical Practice Research Datalink (CPRD) Gold database linked to hospital admissions and emergency care visits. Patients were included if they had a code for acute cardiovascular disease (CVD), depression, road traffic injury, anxiety, self-harm, eating disorder or sleep disorder in their primary or secondary care record, or a code for a psychiatric condition in emergency care, in the 8-week period surrounding the Spring or Autumn clock changes between 2008 and 2019. Negative binomial regression models, adjusted for day of the week and region (and Easter weekend in Spring), compared event rates in the week after the clock changes to the control period (4 weeks before the transitions and weeks 2–4 after).Results In total, 683,809 patients and 1,564,532 events were included in the study. In Spring we found no differences in the number of mental and physical health events in the week after the clock change compared to the control period. In the week after the Autumn transition we found a decrease in acute CVD (IRR 0.98, 95% CI 0.96–0.999), depression (IRR 0.96, 95% CI 0.95–0.97), anxiety (IRR 0.97, 95% CI 0.95–0.98), psychiatric conditions (IRR: 0.94, 95% CI 0.90–0.98) and sleep disorders (IRR 0.92, 95% CI 0.87–0.97).Conclusion The Spring DST transition (when the clocks move forward an hour and people lose sleep) was not associated with changes in the number of health events in primary and secondary care. Meanwhile, the Autumn transition (when the clocks go back an hour and people have the opportunity to gain sleep) was associated with a reduction in acute CVD, sleep disorders and several mental health conditions. These findings suggest that the main impact of the DST transitions on the English health system is a small reduction in demand for health services in the week after the Autumn clock change, particularly for mental health and sleep disorders. We did not find evidence that the DST transitions have a negative impact on the health of the English population.