The present invention relates to an inertial separator for gas liquid separation, comprising: - a tubular body (12) having an inlet (14) extending through a sidewall of the body (12) substantially in tangential direction, - an annular duct (16) arranged inside the tubular body (12) and being in fluid communication with the inlet (14), - wherein the annular duct (16) extends into an interior chamber (18) of the tubular body (12) via an annular gap (20) extending between an inside facing side wall portion (15) of the body (12) and a first insert (30; 50).