Registration lasts for 12 months from the day the anonymous entry is first made on the register.1
Anonymous registrations can be removed earlier in the following circumstances:2
cancellation by the elector
you determine the person is not entitled to be registered
you determine the person was registered, or that their entry was altered, as a result of an application made by another person (i.e. not the individual whose details are provided on the application and who has declared that the information provided is true)
For guidance on removing an elector from the register, see our guidance on deletions.