A downhole tool includes a tubular having an outer surface and an inner surface defining a flowbore having a longitudinal axis. A backpressure valve is arranged in the flowbore. The backpressure valve includes a flapper valve including a first side and an opposing second side pivotally mounted to the inner surface to selectively extend across the flowbore and a locking system including a spring clip mounted to the inner surface. The flapper valve is pivotable between a first position, wherein the flapper valve is free to pivot relative to the inner surface, and a second position, wherein the flapper valve is pivoted away from the flowbore and locked open by the spring clip such that the first side forms part of the flowbore.