A method of handling a call transfer from a circuit switched access network to a packet switched access network, the method comprising: at a Mobile Switching Centre, MSC, Server, receiving a notification that a call for a terminal requires handover from a circuit switched access network to a packet switched access network; at the MSC Server, determining that an IP Multimedia Subsystem network registration of the terminal over the packet switched access network may be used to perform return Single Radio Voice Call Continuity, rSRVCC, by: determining whether the terminal is currently registered in an IP Multimedia Subsystem, IMS, network and whether registration from the MSC Server has been anchored for rSRVCC; in the event that the terminal is not currently registered in the IMS network and/or registration from the MSC Server was not anchored for rSRVCC, invoking an error handling procedure in the MSC Server, and in the event that the terminal is currently registered in the IMS network and the MSC Server is anchored for rSRVCC, invoking return Single Radio Voice Call Continuity to perform a handover of the call from the circuit switched access network to the packet switched access network, wherein the error handling procedure comprises invoking handover from the circuit switched network to a different circuit switched network using procedures other than those of return Single Radio Voice Call Continuity. at a Mobile Switching Centre, MSC, Server, receiving a notification that a call for a terminal requires handover from a circuit switched access network to a packet switched access network; at the MSC Server, determining that an IP Multimedia Subsystem network registration of the terminal over the packet switched access network may be used to perform return Single Radio Voice Call Continuity, rSRVCC, by: determining whether the terminal is currently registered in an IP Multimedia Subsystem, IMS, network and whether registration from the MSC Server has been anchored for rSRVCC; in the event that the terminal is not currently registered in the IMS network and/or registration from the MSC Server was not anchored for rSRVCC, invoking an error handling procedure in the MSC Server, and in the event that the terminal is currently registered in the IMS network and the MSC Server is anchored for rSRVCC, invoking return Single Radio Voice Call Continuity to perform a handover of the call from the circuit switched access network to the packet switched access network, wherein the error handling procedure comprises invoking handover from the circuit switched network to a different circuit switched network using procedures other than those of return Single Radio Voice Call Continuity. determining whether the terminal is currently registered in an IP Multimedia Subsystem, IMS, network and whether registration from the MSC Server has been anchored for rSRVCC; in the event that the terminal is not currently registered in the IMS network and/or registration from the MSC Server was not anchored for rSRVCC, invoking an error handling procedure in the MSC Server, and in the event that the terminal is currently registered in the IMS network and the MSC Server is anchored for rSRVCC, invoking return Single Radio Voice Call Continuity to perform a handover of the call from the circuit switched access network to the packet switched access network, wherein the error handling procedure comprises invoking handover from the circuit switched network to a different circuit switched network using procedures other than those of return Single Radio Voice Call Continuity.