A braking system (1) for an aircraft which includes a by-pass control system (9) for activation when undemanded braking or loss of braking is detected. The braking system (1) comprises: a brake pedal transducer (2) for generating a brake pedal actuation signal when a brake pedal (3) is applied; brake actuation means (5) for activating a brake (6) on receipt of a braking signal; braking pressure transducer means (7) for generating a braking output signal related to the braking force applied to the brake (6); primary processing means (4) in electrical communication with the brake pedal transducer (2) and the brake actuation means (5) and adapted to generate a braking signal on receipt of a brake pedal actuation signal; secondary processing means (8) adapted to receive the brake pedal actuation signal and braking output signal; and a bypass braking control system (9) adapted to receive the brake pedal actuation signal from the brake pedal transducer (2) and generate a braking signal in response to the brake pedal actuation signal. The secondary processing means (8) is adapted to disable the primary processing means (4) and enable the bypass braking control system (9) on detection of undemanded braking or loss of braking from the brake pedal actuation signal and braking output signal.