A silicon neuron circuit that produces spiking and bursting firing patterns, with biologically plausible spike shape, is presented. The circuit mimics the behaviour of known classes of cortical neurons: regular spiking (RS), fast spiking (FS), chattering (CH) and intrinsic bursting (IB). The paper describes the operation of the circuit, provides simulation results, a simplified analytical model, and a phase-plane analysis of its behaviour. The functionality of the circuit has been verified experimentally. The paper introduces a proof-of-concept analogue integrated circuit, implemented in a 0.35 μm CMOS technology, and presents preliminary measurement results. The neuron cell provides an area and energy efficient implementation of the silicon cortical neuron, and could be used as a universal neuron circuit in VLSI neuromorphic networks that closely resemble the circuits of the cortex.