This paper introduces a novel paradigm to address the challenge of concurrently optimising the topology and anisotropy of a variable-stiffness composite structures from additive manufacturing technology. The proposed approach is based on a multi-scale two-level optimisation strategy, which relies on non-uniform rational basis spline (NURBS) entities and the polar formalism. NURBS entities are used to describe both the topology and the distribution of the polar parameters and the thickness over the structure. A unified formulation of laminate-level failure criteria is presented, and the notion of failure load is introduced in the problem formulation to obtain optimised solutions that do not depend on the magnitude of the applied loads. In this context, the formal expression of the gradient of the design requirements is derived by taking advantage of the properties of the NURBS entities. The effectiveness of the approach is then tested on a series of benchmark problems taken from existing literature.