An authentication method comprising: comparing user voice data received via an electronic device to a stored voice template to determine a voice authentication parameter; determining a voice authentication threshold; and comparing the voice authentication parameter to the voice authentication threshold to determine whether to authenticate the user; wherein determining the voice authentication threshold comprises: determining a current value of an enrolment counter indicating a number of times the stored voice template was modified since an initial enrolment process, or indicating a number of voice samples used to create the stored voice template; comparing the current value of the enrolment counter to an enrolment counter threshold and determining whether the stored voice template is fully enrolled according to the result; if the stored voice template is fully enrolled, setting the voice authentication threshold to a first voice authentication threshold; and if the stored voice template is not fully enrolled: comparing a device attribute received from the electronic device to a stored device attribute; if the received device attribute matches the stored device attribute, setting the voice authentication threshold to a second voice authentication threshold determined by the current value of the enrolment counter; and if the received device attribute does not match the stored device attribute, setting the voice authentication threshold to a third voice authentication threshold. comparing user voice data received via an electronic device to a stored voice template to determine a voice authentication parameter; determining a voice authentication threshold; and comparing the voice authentication parameter to the voice authentication threshold to determine whether to authenticate the user; wherein determining the voice authentication threshold comprises: determining a current value of an enrolment counter indicating a number of times the stored voice template was modified since an initial enrolment process, or indicating a number of voice samples used to create the stored voice template; comparing the current value of the enrolment counter to an enrolment counter threshold and determining whether the stored voice template is fully enrolled according to the result; if the stored voice template is fully enrolled, setting the voice authentication threshold to a first voice authentication threshold; and if the stored voice template is not fully enrolled: comparing a device attribute received from the electronic device to a stored device attribute; if the received device attribute matches the stored device attribute, setting the voice authentication threshold to a second voice authentication threshold determined by the current value of the enrolment counter; and if the received device attribute does not match the stored device attribute, setting the voice authentication threshold to a third voice authentication threshold. determining a current value of an enrolment counter indicating a number of times the stored voice template was modified since an initial enrolment process, or indicating a number of voice samples used to create the stored voice template; comparing the current value of the enrolment counter to an enrolment counter threshold and determining whether the stored voice template is fully enrolled according to the result; if the stored voice template is fully enrolled, setting the voice authentication threshold to a first voice authentication threshold; and if the stored voice template is not fully enrolled: comparing a device attribute received from the electronic device to a stored device attribute; if the received device attribute matches the stored device attribute, setting the voice authentication threshold to a second voice authentication threshold determined by the current value of the enrolment counter; and if the received device attribute does not match the stored device attribute, setting the voice authentication threshold to a third voice authentication threshold. comparing a device attribute received from the electronic device to a stored device attribute; if the received device attribute matches the stored device attribute, setting the voice authentication threshold to a second voice authentication threshold determined by the current value of the enrolment counter; and if the received device attribute does not match the stored device attribute, setting the voice authentication threshold to a third voice authentication threshold.