A control section for a vapour provision system, the control section being configured to be separably connectable with a cartomiser section, the cartomiser section and the control section together forming the vapour provision system, wherein: the control section comprises a control circuit (100; 200; 300); the cartomiser section comprises an electrical heating element; the vapour provision system further comprises a battery; and the control circuit (100; 200; 300) comprises: a first controller with capability to control a first set of components (34; 50) in the vapour provision system; a second controller with capability to control a second set of components (34; 50) in the vapour provision system, at least one component in the second set being also in the first set; and a communication link between the first controller and the second controller by which at least one controller can monitor operation of the other controller; wherein: the first controller and the second controller have capability to control the at least one component by switching it between an on state and an off state; the at least one component comprises the electrical heating element, and the capability to control the at least one component comprises controlling provision of electrical power from the battery to the electrical heating element; and one or both controllers is operable to, via the communication link, detect a fault with the capability of the other controller to control the at least one component and, in response, assume control of the at least one component. the control section comprises a control circuit (100; 200; 300); the cartomiser section comprises an electrical heating element; the vapour provision system further comprises a battery; and the control circuit (100; 200; 300) comprises: a first controller with capability to control a first set of components (34; 50) in the vapour provision system; a second controller with capability to control a second set of components (34; 50) in the vapour provision system, at least one component in the second set being also in the first set; and a communication link between the first controller and the second controller by which at least one controller can monitor operation of the other controller; wherein: the first controller and the second controller have capability to control the at least one component by switching it between an on state and an off state; the at least one component comprises the electrical heating element, and the capability to control the at least one component comprises controlling provision of electrical power from the battery to the electrical heating element; and one or both controllers is operable to, via the communication link, detect a fault with the capability of the other controller to control the at least one component and, in response, assume control of the at least one component. a first controller with capability to control a first set of components (34; 50) in the vapour provision system; a second controller with capability to control a second set of components (34; 50) in the vapour provision system, at least one component in the second set being also in the first set; and a communication link between the first controller and the second controller by which at least one controller can monitor operation of the other controller; wherein: the first controller and the second controller have capability to control the at least one component by switching it between an on state and an off state; the at least one component comprises the electrical heating element, and the capability to control the at least one component comprises controlling provision of electrical power from the battery to the electrical heating element; and one or both controllers is operable to, via the communication link, detect a fault with the capability of the other controller to control the at least one component and, in response, assume control of the at least one component. the first controller and the second controller have capability to control the at least one component by switching it between an on state and an off state; the at least one component comprises the electrical heating element, and the capability to control the at least one component comprises controlling provision of electrical power from the battery to the electrical heating element; and one or both controllers is operable to, via the communication link, detect a fault with the capability of the other controller to control the at least one component and, in response, assume control of the at least one component.