A method of controlling a wind turbine, where a control signal for a controllable parameter of the wind turbine is determined repeatingly at successive time steps, and a control history including respective control values derived from or included in past control signals is stored. These control values stored in the control history are then used to determine an alert parameter for the controllable parameter, the alert parameter being a function of the variations of the control signals over time. The wind turbine is then controlled according to the most recent control signal only if the alert parameter is below an alert threshold, and otherwise according to a modified control strategy. The control method may be performed on pitch reference signals for controlling the individual and/or collective pitch of the blades. The invention further relates to a control system configured to perform the above control method, and a wind turbine comprising such system.