a method for cutting an underwater structure below the level of the seabed on which it is installed is described . the method has the following steps : positioning cutting means and penetrating means associated with the cutting means in close proximity to the underwater structure to be cut , at the intersection region between the structure and the seabed ; causing both the penetrating means and the cutting means associated therewith to penetrate into the seabed in a substantially longitudinal direction to a portion of the structure which is embedded in the seabed ; and actuating and driving the cutting means and the penetrating means in a substantially perpendicular direction to the embedded portion so as to cut the structure below the level of the seabed . an apparatus for carrying out the method is also described .