Correlation circuitry includes selection circuitry for selecting a sequence of symbol subsets comprising proper subsets of a candidate sequence of symbols and corresponding proper subsets of a target sequence of symbols. Correlation value determining circuitry determines partial correlation values for these proper subsets which are then combined by correlation value combining circuitry to generate a current combined correlation value. Early termination circuitry compares the current combined correlation value with an early termination condition represented by a threshold value to determine whether or not early termination of the correlation determination may be performed. Early termination may be performed when the combined correlation value indicates a sufficient degree of confidence in the partial result determined such that continuing with determination of the full correlation is not justified.