I shall now make some headway. The provision is designed to ensure that orders reflect changing circumstances and do not remain in force for perpetuity without further consideration. Parties subject to orders may themselves request that the Secretary of State vary or revoke their order. This is another mechanism to ensure that orders remain appropriate. The Secretary of State must consider such requests unless the request relates to a final order and, in the opinion of the Secretary of State, there has been no material change in circumstances since the order was made or last varied, or if the party concerned has previously made a request to vary or revoke the order since that request.