A wind turbine having at least one trailing edge control surface (10) on at least one rotor blade (5) is operated in a first mode, in which a rotor blade angle of attack and a trailing edge control surface deflection are set according to one or more wind turbine control parameters. The turbine is selectively operated in a second, noise reduced, mode, in which for a given set of wind turbine control parameters, the trailing edge control surface deflection is increased towards the pressure side and the rotor blade angle of attack is decreased with respect to the first mode. In the second mode, for a given set of control parameters, the loading on the blade (5) is on average closer to a hub than in the first operating mode.