The River Hull Tidal Surge Barrier is located at the confluence of the rivers Hull and Humber to exclude surge tides from the River Hull. The concept of the unusual turnover lift gate and its control system is set out, together with details of the design of the gate, the superstructure and the foundations. Construction included one of the deepest single-stage cofferdams in the UK, and an account is given of the design and practical problems encountered. The project included some unusual architectural features, ancillary flood defences and a telemetry system.