For example, you may be seeking to establish that your development or use of a property is lawful by virtue of the time that has elapsed since it has been used or built.
In such cases, the onus is on the applicant to prove ‘on the balance of probability’ that the development or use is lawful.
If the LPA refuses such an application for a lawful development certificate then you can appeal that decision, and the Planning Inspectorate will review your submission.
The Planning Inspectorate will not be considering the planning merits of your proposal, just whether the evidence that you have provided is sufficient to prove the lawfulness of the development or not.
The full procedure for submitting a lawful development certificate appeal is available on GOV.UK.