An asynchronous implementation of the ARM microprocessor is described. The design is based on Sutherland's Micropipelines, and allows considerable internal asynchronous concurrency. The rationale for the work is presented, the organisation of the chip described, and the characteristics of the chip described. The design displays unusual properties such as nondeterministic (but bounded) prefetch depth beyond a branch instruction. This work demonstrates the feasibility of building complex asynchronous systems and gives an indication of the costs and benefits of the Micropipeline approach.