 Patients presenting to the emergency department with acute ischemic stroke, who are are eligible for standard intravenous tPA therapy within 4.5 hours of stroke onset will be assessed for major vessel occlusion to determine their eligibility for randomization into the trial. If the patient gives informed consent they will be randomised 50:50 using central computerised allocation to intravenous alteplase or tenecteplase before all participants undergo intra-arterial clot retrieval. The trial is prospective, randomised, open-label, blinded endpoint PROBE design. 