The present invention provides a surgical clamp comprising a temperature sensitive shape memory material, the clamp capable of taking up a first form in which the clamp (6) is shaped to at least partially encircle a tubular structure (14); a second form shaped to substantially completely encircle the tubular structure (14) and constrict it, the clamp changing from the first form to the second form above the transition temperature of the shape memory material; and a third form derived from the first form by resilient deformation of the clamp in its first form. The present invention also provides applicators for delivering the clamps and kits comprising the clamps.