Abstract: A brake system for a vehicle comprises a driver operable brake pedal coupled to control a brake pressure generating unit to supply hydraulic brake pressure to front and rear hydraulically actuated wheel brakes, and wherein the rear wheel brakes are also configured to be electrically actuated; a sensor arrangement for monitoring the driver's braking intent; the brake system operable in a first mode wherein the front and rear brakes are both hydraulically actuated, and a second mode wherein the front brakes are hydraulically actuated and the rear brakes are electrically actuated, the rear brakes include a caliper assembly including brake pads operable to engage a brake rotor to brake the vehicle, the caliper assembly including a hydraulic actuating mechanism and an electric actuating mechanism, a control connected to the sensor arrangement for operating the electric actuating mechanism to actuate the rear brakes as a function of the driver's braking demand.