A system comprising: a first controller operable to assume one of a plurality of respective states, in a first state the first controller being configured to generate a first controller powertrain signal in order to cause a powertrain to develop drive torque and cause a vehicle to operate in accordance with a target speed value; and a second controller configured to receive from the first controller a state signal responsive to the state assumed by the first controller and the first controller powertrain signal, the second controller being configured to cause a powertrain to deliver an amount of drive torque according to the first controller powertrain signal in dependence on the state signal; wherein the first controller is configured to generate a first controller brake request signal in order to request application of a brake (111B, 112B, 114B, 115B) to one or more wheels (111, 112, 114, 115) thereby to cause the vehicle to operate in accordance with the target speed value; characterized in that the system comprises a third controller configured to receive the first controller brake request signal from the first controller and to cause application of a brake (111B, 112B, 114B, 115B) to one or more wheels (111, 112, 114, 115) of the vehicle in dependence on the first controller brake request signal, the first controller being configured to assume the first state in which the first controller is configured to cause the vehicle to operate in accordance with the target speed value or a second state in which the first controller is substantially inactive and is configured not cause the vehicle to operate in accordance with the target speed value, and a third state in which the first controller causes the vehicle to operate in accordance with the target speed value by application of a brake (111B, 112B, 114B, 115B) to one or more wheels (111, 112, 114, 115) and not by application of drive torque; wherein when the first controller is in the third state the third controller is configured to cause application of a brake (111B, 112B, 114B, 115B) to one or more wheels (111, 112, 114, 115) of the vehicle in dependence on the first controller brake signal, and wherein the second controller suspends application of positive drive torque to one or more wheels (111, 112, 114, 115) in response to the first controller powertrain signal. a first controller operable to assume one of a plurality of respective states, in a first state the first controller being configured to generate a first controller powertrain signal in order to cause a powertrain to develop drive torque and cause a vehicle to operate in accordance with a target speed value; and a second controller configured to receive from the first controller a state signal responsive to the state assumed by the first controller and the first controller powertrain signal, the second controller being configured to cause a powertrain to deliver an amount of drive torque according to the first controller powertrain signal in dependence on the state signal; wherein the first controller is configured to generate a first controller brake request signal in order to request application of a brake (111B, 112B, 114B, 115B) to one or more wheels (111, 112, 114, 115) thereby to cause the vehicle to operate in accordance with the target speed value; characterized in that the system comprises a third controller configured to receive the first controller brake request signal from the first controller and to cause application of a brake (111B, 112B, 114B, 115B) to one or more wheels (111, 112, 114, 115) of the vehicle in dependence on the first controller brake request signal, the first controller being configured to assume the first state in which the first controller is configured to cause the vehicle to operate in accordance with the target speed value or a second state in which the first controller is substantially inactive and is configured not cause the vehicle to operate in accordance with the target speed value, and a third state in which the first controller causes the vehicle to operate in accordance with the target speed value by application of a brake (111B, 112B, 114B, 115B) to one or more wheels (111, 112, 114, 115) and not by application of drive torque; wherein when the first controller is in the third state the third controller is configured to cause application of a brake (111B, 112B, 114B, 115B) to one or more wheels (111, 112, 114, 115) of the vehicle in dependence on the first controller brake signal, and wherein the second controller suspends application of positive drive torque to one or more wheels (111, 112, 114, 115) in response to the first controller powertrain signal.