Extrusion die

An extrusion die comprising a die body having a die cavity formed therein, the die body defining a male portion which projects into a female portion, a recess of non-uniform depth being provided on the die body ahead of the die cavity in the extrusion direction, the recess being of non-uniform depth both around and across the die cavity, wherein a leading edge of a part of the die cavity defined by the male portion and a leading edge of an opposing part of the die cavity defined by the female portion are out of alignment with one another when the die is not in use, at least part of at least one of the leading edges being defined at the intersection between the die cavity and the recess, wherein the die body has a leading face wherein the die cavity is formed, and wherein the leading face is non-planar whereby the male portion is raised relative to the female portion resulting in the leading edge of the part of the die cavity defined by the male portion being spaced, in the extrusion direction, ahead of the leading edge of the part of the die cavity defined by the female portion by a distance which is not uniform around the die cavity, the spacing being such that deflection of the male portion, in use, brings the leading edges substantially into alignment.