Introduction: Endovascular thrombectomy is a highly effective treatment for acute ischemic stroke due to large arterial occlusion. Routine provision will require major changes in service configuration and workforce. An important first step is to quantify the population of stroke patients that could benefit. We estimated the annual UK population suitable for endovascular thrombectomy using standard or advanced imaging for patient selection. Patients and methods: Evidence from randomised control trials and national registries was combined to estimate UK stroke incidence and define a decision-tree describing the endovascular thrombectomy eligible population. Results: Between 9620 and 10,920 UK stroke patients (approximately 10% of stroke admissions) would be eligible for endovascular thrombectomy annually. The majority (9140–9620) would present within 4 h of onset and be suitable for intravenous thrombolysis. Advanced imaging would exclude 500 patients presenting within 4 h, but identify an additional 1310 patients as eligible who present later. Discussion: Information from randomised control trials and large registry data provided the evidence criterion for 9 of the 12 decision points. The best available evidence was used for two decision points with sensitivity analyses to determine how key branches of the tree affected estimates. Using the mid-point estimate for eligibility (9.6% of admissions) and assuming national endovascular thrombectomy coverage, 4280 patients would have reduced disability. Conclusion: A model combining published trials and register data suggests approximately 10% of all stroke admissions in the UK are eligible for endovascular thrombectomy. The use of advanced imaging based on current published evidence did not have a major impact on overall numbers but could alter eligibility status for 16% of cases.