Is the Commissioner’s decision final?

Once the Commissioner has issued his decision it concludes his involvement in a complaint.
A complainant who wishes to challenge the Commissioner’s decision can apply to the High Court (at their own expense) to seek leave to apply for a judicial review of the Commissioner’s decision. The Court itself has to give leave before it considers whether or not there should be a judicial review of the decision.
An application for leave to apply for judicial review must be made to the Administrative Court Office at the Royal Courts of Justice within three months of the date of the Commissioner’s decision letter. A complainant who wishes to consider doing this may wish to seek their own legal advice (which will be at their own cost) before approaching the High Court, since complex legal issues may arise.