A leak detection system for detecting leaks in pressurized containers, the system comprising a leak test conveyor for moving each container and an accumulation tunnel through which the leak test conveyer extends, wherein the accumulation tunnel and the leak test conveyer together define at least one enclosed accumulation volume, each enclosed accumulation volume being sized to accommodate only a single container, thereby to allow gas leaking from the single container to accumulate, and a gas sensor for sensing accumulated leaked gas from the single container.