A packet data network gateway, P-GW, is located in a second network for supporting control plane data in a wireless communications system that additionally comprises a first network having a first P-GW operably couplable to the P-GW, and a serving gateway, S-GW. The P-GW comprises a processor arranged to: monitor and build terminal device context information for a plurality of terminal devices being served with user plane data by the second network; and determine an operational status of at least one of: the backhaul link, first P-GW. In response to the processor determining that at least one of: the backhaul link, first P-GW, is unavailable, the processor is arranged to perform at least one of: terminate signalling between the first network and at least one of a mobility management entity, MME, the S-GW; defer signalling between the first network and at least one of the MME, the S-GW; perform at least some functionality of the first P-GW.