Once a licence has been granted, installation should take place within one year. Failure to do so may mean that the licence is terminated and subject to a reapplication which is at the discretion of the network manager. This period of validity is required as the highway may have changed requiring different conditions to be placed upon a licence.
Licences are checked annually to ensure that a Section 171 permit has been cross referenced and a licensee may be contacted if no works have been carried out to ensure the licence is still required. If it is not, the licence will be terminated.