A circuit performs a turbo detection process recovering data symbols from a received signal effected, during transmission, by a Markov process with effect that the data symbols are dependent on preceding data symbols represented as a trellis having a plurality of trellis stages. The circuit comprises processing elements, associated with trellis stages representing these dependencies and each configured to receive soft decision values corresponding to associated data symbols Each processing element configured, in one clock cycle to receive data representing a priori forward and backward state metrics, and a priori soft decision values for data symbols detected for the trellis stage. For each clock cycle of the turbo detection process, the circuit processes, for processing elements representing the trellis stages, the a priori information for associated data symbols detected for the trellis stage, and to provide extrinsic soft decision values corresponding to data symbols for a next clock cycle.