Deputy
A person appointed by the Court of Protection to make decisions for someone who has lost capacity without an LPA in place.
A Deputy plays a similar role to an attorney under an LPA, but is appointed by the Court rather than chosen by the person who has lost capacity. Deputies are supervised by the Office of the Public Guardian throughout their appointment, with annual reports and (in many cases) a security bond.
Putting an LPA in place while you have capacity avoids the need for a Deputy. It is cheaper, faster and gives you control over who acts for you.