A hydraulic system for a vehicle having first and second brakes (12, 14), comprising a source of hydraulic fluid (16a, 16b), a first brake valve and a second brake valve, each of the first and second brake valves (18a, 18b) having a pressure inlet (20a, 20b), an exhaust outlet (22a, 22b) and a control inlet (24a, 24b); the first and second brake valves (18a, 18b) being arranged in a parallel configuration, wherein the pressure inlet (20a, 20b) of each of the first and second brake valves is connected to the source of hydraulic fluid (16a, 16b), and the exhaust outlet (22a, 22b) of each of the first and second brake valves is connected to a respective one of the first and second brakes (12, 14); wherein either: (a) each of the first and second brake valves (18a, 18b) is responsive to a braking signal in the form of actuation of a foot pedal by an operator of the vehicle to permit hydraulic fluid to flow from said source of hydraulic fluid (16a, 16b) to apply the respective one of the first and second brakes (12, 14), or (b) the control inlet (24a, 24b) of each respective one of the first and second brake valves is directly responsive to a braking signal from an operator of the vehicle to control the respective one of the first and second brake valves (18a, 18b) to permit hydraulic fluid to flow from said source of hydraulic fluid (16a, 16b) to apply the respective one of the first and second brakes (12, 14); and further including a first control valve and a second control valve, each connected to the source of hydraulic fluid (16a, 16b); characterised in that the first and second control valves (50a, 50b) are responsive to control signals (52a, 52b) to selectively provide hydraulic fluid from said source of hydraulic fluid (16a, 16b) to the control inlet (24a, 24b) of the first and second brake valves (18a, 18b), respectively, to control the first and second brake valves (18a, 18b) to permit hydraulic fluid to flow from said source of hydraulic fluid (16a, 16b) to apply the first and second brakes (12, 14) independently of the operator of the vehicle. the first and second brake valves (18a, 18b) being arranged in a parallel configuration, wherein the pressure inlet (20a, 20b) of each of the first and second brake valves is connected to the source of hydraulic fluid (16a, 16b), and the exhaust outlet (22a, 22b) of each of the first and second brake valves is connected to a respective one of the first and second brakes (12, 14); wherein either: (a) each of the first and second brake valves (18a, 18b) is responsive to a braking signal in the form of actuation of a foot pedal by an operator of the vehicle to permit hydraulic fluid to flow from said source of hydraulic fluid (16a, 16b) to apply the respective one of the first and second brakes (12, 14), or (b) the control inlet (24a, 24b) of each respective one of the first and second brake valves is directly responsive to a braking signal from an operator of the vehicle to control the respective one of the first and second brake valves (18a, 18b) to permit hydraulic fluid to flow from said source of hydraulic fluid (16a, 16b) to apply the respective one of the first and second brakes (12, 14); and further including (a) each of the first and second brake valves (18a, 18b) is responsive to a braking signal in the form of actuation of a foot pedal by an operator of the vehicle to permit hydraulic fluid to flow from said source of hydraulic fluid (16a, 16b) to apply the respective one of the first and second brakes (12, 14), or (b) the control inlet (24a, 24b) of each respective one of the first and second brake valves is directly responsive to a braking signal from an operator of the vehicle to control the respective one of the first and second brake valves (18a, 18b) to permit hydraulic fluid to flow from said source of hydraulic fluid (16a, 16b) to apply the respective one of the first and second brakes (12, 14); and further including a first control valve and a second control valve, each connected to the source of hydraulic fluid (16a, 16b); characterised in that the first and second control valves (50a, 50b) are responsive to control signals (52a, 52b) to selectively provide hydraulic fluid from said source of hydraulic fluid (16a, 16b) to the control inlet (24a, 24b) of the first and second brake valves (18a, 18b), respectively, to control the first and second brake valves (18a, 18b) to permit hydraulic fluid to flow from said source of hydraulic fluid (16a, 16b) to apply the first and second brakes (12, 14) independently of the operator of the vehicle.