Abstract: The invention relates to an electrical system for use in a vehicle. The electrical system comprises a controller and electrically operable vehicle brake means. The electrical system comprises at least one vehicle electric load including vehicle brake control means operable to selectively control the vehicle brake means to move between an engaged position in which the vehicle brake means acts to inhibit movement of the vehicle and a disengaged position in which the vehicle brake means does not act to inhibit movement of the vehicle. The electrical system also comprises first and second batteries for providing electric power to the vehicle brake means and the at least one vehicle electric load. In response to detection of a fault in the electrical system, the controller is operable to electrically isolate the second battery and the vehicle brake means from the first battery and the at least one vehicle electric load, and the vehicle brake means is configured to automatically assume the engaged position.