Abstract: This disclosure relates to security tags and in particular to electronic article surveillance (EAS) tags that are applied to items in a retail environment to deter theft of the items. A security tag comprises a main body, a tamper element and circuitry housed in the main body, the main body being connectable to the tamper element such that the tamper element completes a tamper circuit. The circuitry comprises an alarm system configured to be triggered when the tamper circuit is opened, a switch having a first state in which the alarm system is activated and a second state in which the alarm system is deactivated, and a latch element arranged to detect the state of the switch and being configured such that when the state of the switch changes from the first state to the second state the alarm system is permanently disabled.