Abstract: A subsea plough includes a plough share coupled to a chassis, boulder clearance and spoil clearance members, and front and rear support surfaces. In a first configuration, a maximum span of the boulder clearance member in an extended position is greater than a span of the spoil clearance member. The plough may be reconfigurable to include a backfill member. A method of use of the plough is provided in a boulder clearing only mode, and optional modes of simultaneous boulder clearing and trenching, second pass trenching, and backfilling a trench to bury a flexible elongate member in a seabed.