Abstract: A pipeline safety joint to provide a controlled point of weakness in at least one pipeline, said safety joint comprising a pair of tubular mandrels sized to be securable to a pipe-end of a pipeline, a portion of one mandrel being insertable into a part of the other mandrel thereof, to provide fluid communication between said pipe-ends. A latch mechanism on the portion of one mandrel is engagable with the part of the other mandrel, to hold said mandrel against axial separation. Retaining means on said one mandrel hold the latch mechanism in engagement. At least one seal assembly includes a metal sealing ring positioned to seal between a radially outer and inner substantially cylindrical surfaces on the mandrels. An annular cylinder and a co-operating annular piston formed on one mandrel and on a ring attached to the mandrel, to form a pressure compensation chamber surrounding said portion rings provide a fluid tight seal between said annular piston and cylinder.