A surgical cutting guide is described which can guide a cutting implement to cut in a pair of planes at a defined relative orientation. The cutting guide comprises a first plate defining a first cutting plane, a second plate defining a second cutting plane at an angle to the first cutting plane; and a base member to which both the first plate and the second plate are attached. The first and second cutting planes intersect each other at a line of intersection and both the first plate and the second plate extend beyond the line of intersection.