Should an applicant want written confirmation of the extension to the commencement date, they should contact the relevant local planning authority to which the permission relates. Local planning authorities should work constructively with the applicant to provide written confirmation of the extension to the commencement date and aim to provide a response as quickly as possible so that applicants have the certainty to carry out development lawfully. In cases of doubt, an applicant may apply for a certificate of lawfulness of proposed development under section 192 of the Town and Country Planning Act 1990.