When a person becomes mentally incapable of handling their own affairs, they are usually incapable of delegating that responsibility to someone else. Consequently, unless provision has been made for such a situation in the form of an Enduring Power of Attorney, the usual way to deal with those affairs is to appoint another person under the Mental Health Act 1983, by way of an Order of the Court of Protection or a Direction of the Public Trustee.
Where a person is or is becoming mentally incapable and has made an Enduring Power of Attorney, the attorney(s) has a duty to apply for registration. The Enduring Power of Attorney is inoperative unless it has been registered.