If given verbally, authorisations must be confirmed in writing as soon as reasonably practicable, and in either case must be notified to the Home Office as soon as reasonably practicable. Authorisations must be confirmed by the Home Office within 48 hours of their being made, or they expire automatically. If confirmed, an authorisation can only last for up to 14 days. An authorisation can be cancelled at any time, or restricted in respect of the time it ends or the area which it covers, but it cannot be expanded. New authorisations can be made regardless of whether previous authorisations exist, or have been cancelled or have expired.