A bi-directional pipeline tool has a body or location in a pipe. A seal element is mounted on the body, the seal element having oppositely directed seal portions with a first seal portion directed towards a first side of the body and a second seal portion directed towards a second side of the body. A valve is provided in the body, the valve having a first port for communicating with fluid on the first side, a second port for communicating with fluid on the second side, and a third port for providing access to a chamber between the seal element and the body. In use, a pressure differential is developed across the tool between fluid upstream of the tool and fluid downstream of the tool. The valve permitting activation of the downstream seal portion, whichever of the portions is the downstream seal portion, by the upstream fluid pressure.