A power of attorney is a legal document that hands your decisions to someone else, called an attorney, if illness, injury or absence stops you making them yourself. The person who grants it is the “donor”. The attorney they name can act on their behalf once the document takes effect.

The document only works while you still have the mental capacity to sign it. Once that capacity is gone, the choice is no longer yours to make.

What it lets someone do

In England and Wales, a lasting power of attorney splits into two kinds. A health and welfare LPA covers care and medical choices, and only takes effect once the donor loses capacity. A property and financial affairs LPA covers money and assets. It can be used as soon as it is registered, even while the donor can still decide for themselves.

Scotland and Northern Ireland run their own versions rather than the English one. Scotland splits the same way, into a continuing power of attorney for money and a welfare power of attorney for health and care. Northern Ireland’s ordinary power of attorney covers finances but stops the moment capacity is lost, while its enduring power of attorney carries on. Every version, in every UK nation, has to be registered with the relevant authority before an attorney can use it.

The underlying law differs more than the shared name suggests. England and Wales run on the Mental Capacity Act 2005, which treats everyone aged 16 or over as having capacity unless it is shown otherwise, and requires any decision made for them to serve their best interests. Scotland’s equivalent, the Adults with Incapacity (Scotland) Act 2000, sets up its own supervising body: the Office of the Public Guardian for Scotland. It shares a name with its English counterpart but is a separate organisation.

Who can make one, and what it costs

Anyone with the mental capacity to understand what they are signing can grant a power of attorney. In England, Wales and Northern Ireland the minimum age is 18. In Scotland it is 16. Setting one up in England and Wales starts at £92 per LPA, with fee reductions available for some donors.

What happens without one

If someone loses capacity with no power of attorney in place, their family cannot simply step in. A relative has to apply to the Court of Protection to be appointed as a “deputy”, a process that can take months and involve significant costs. Bank accounts can stay frozen while that goes on. The court is not obliged to appoint the person the donor would have chosen. Decisions may instead fall to doctors or social workers acting on their view of the person’s “best interests”, which may not match the person’s own preferences.

Guarding against misuse

An attorney’s power invites a real worry: what stops them acting against the donor’s wishes. The Law Society advises solicitors that every decision an attorney makes under the Mental Capacity Act must serve the donor’s best interests. A donor can also limit what an attorney is allowed to do, or name more than one attorney who must act jointly on major decisions.

Misuse is rare but does happen. Unexplained withdrawals, secrecy about money, unpaid bills despite available funds, and an attorney mixing the donor’s money with their own are the warning signs. Anyone concerned can report it to the Office of the Public Guardian, which has the power to investigate.

Around 40% of people over 70 have a power of attorney arranged. The document only stays an option for as long as the person granting it still has the capacity to choose.