Third-party mandates and letters of authority

A third-party mandate is a document telling your bank that someone you trust is allowed to run your personal accounts¹. You set it up while you still have the mental capacity to give that permission, and you can specify how much access to give, from making payments to taking money out in your name². It is one of the simplest ways to let a relative, friend or carer help with day-to-day banking, and most banks have a third-party mandate form on their website³.

A mandate is not the same as a power of attorney, and the difference matters. A third-party mandate does not give the helper any legal right to make decisions about your finances; it is permission you grant, which the bank can accept or refuse⁴. It also has a hard limit: third-party mandates end when the account holder loses mental capacity⁵. If you are arranging help for the longer term, or for a time when you may not be able to make decisions, a lasting power of attorney is usually the sturdier option, though it takes longer to set up.

What a third-party mandate lets someone else do

A third-party mandate gives someone else access to your bank account, and you can specify how much access to give². In practice, the person you nominate will usually be able to take out money in your name, make payments in your name, and make other transactions in your name⁶. Depending on the bank's own arrangements, the person helping you can have their own card and PIN, so they can use cash machines and pay in shops without you being present⁶.

The mandate works because you, the account holder, give permission. That is its strength and its boundary. Guidance for people acting for someone else is clear that you need permission from the person to get a third-party mandate, and that the mandate does not give you the legal right to make decisions about their finances⁴. The helper is an operator of the account, not an owner and not a decision-maker in law. Money paid out under the mandate is the account holder's money, and the account remains theirs throughout.

This makes a mandate well suited to a defined, practical job: a partner paying bills from your account while you are in hospital, a son or daughter managing your day-to-day spending while you recover, or a friend collecting your pension and doing your shopping during a long illness. Charities that support people with cancer and with disabilities describe exactly this use, where someone trustworthy is given the mechanics of the account for a period¹. It is quick, it is free, and it keeps you in charge, because you decide who the helper is and how much they can do.

Where a mandate stops: overdrafts, new accounts and closures

A mandate's reach is narrower than full account ownership. Which? notes that a third-party mandate allows calls, querying statements and operating the account, but the helper will not be allowed to arrange a formal overdraft or open or close an account⁵. Those steps are reserved to the account holder, because they change the bank's relationship with its customer rather than simply operating within it.

The overdraft limit is worth understanding, because overdrafts sit at the edge of what a helper can touch. If the account is using its overdraft, the overdraft must be paid back before the account can be closed, and access to statements is lost once it is closed, so copies of any statements needed later have to be kept beforehand⁷. When switching accounts with an overdraft, the new bank may agree to take on the debt: if the new overdraft covers what is owed, the funds are sent to the old bank and the overdraft balance is owed on the new account instead; if it is a lower amount, or no new overdraft can be obtained, the remainder has to be arranged to be paid off separately before the old account can be switched or closed⁷.

There are also rules about how banks treat people in overdraft, which can matter to the account holder even when a helper is running things. The FCA's rules on overdraft repeat use apply to any customers who are showing signs of financial strain or are in financial difficulty⁸, and firms are expected to identify options for them, which may include advice on budgeting and money management, forbearance such as reducing or waiving interest and other charges, refinancing to an alternative credit agreement on more favourable terms, or agreeing staged reductions in the overdraft limit and balance⁹. The rules capture any charges that arise because a customer has used an overdraft, or that are triggered by the fact that the account has entered, remains in, or extended a debit position¹⁰.

Two further points sit around the edges of a mandate. First, if you have an overdraft or other debts on your current account and you open a basic bank account at the same bank, the bank may use the money in the new basic account to pay off debts in the old overdrawn account, so it can be worth opening the basic account at a different bank if you receive benefits, tax credits or a state pension¹¹. Second, a mandate is not the only "third party" arrangement a bank may be involved in: councils can apply for third-party deductions from certain benefits once a summary warrant has been issued, without having to serve a charge for payment, to cover household bills such as electricity or rates arrears, court fines and child maintenance¹². And if a creditor gets a final third party debt order against your account, it allows the creditor to take the money you owe directly from whoever has the money, though if your account is overdrawn on the day the order is sent to your bank, the creditor will not get their money as there will not be enough funds¹⁴.

Speaking to a firm for someone: letters of authority and information

A third-party mandate is about operating an account. A letter of authority is the lighter tool for speaking on someone's behalf: a signed statement telling a firm that a named person may ask questions and receive information about the account. Mental Health and Money Advice notes that a third-party mandate will allow someone to operate your account in the same way as a letter of authority, so for banking the mandate tends to be the fuller instrument¹⁵.

For firms outside banking, the letter is often all that is needed for information. The ICO, which oversees data protection, says you can ask someone else to submit a request for you, but they will need to send the organisation proof that they are authorised to act on your behalf, such as written permission or a power of attorney document¹⁶. Pension bodies take the same approach: SPPA in Scotland states that if a request is from a third party, for example an independent financial advisor, the member must provide a signed mandate authorising release of information before any information is released¹⁷.

In practice this means a helper with a letter of authority can usually phone up, query a statement, chase a payment or ask a firm to explain a charge. What they generally cannot do is change the arrangement itself: instruct a withdrawal, close the account or agree a new contract. Those actions need either the account holder, a third-party mandate where the bank allows it, or a power of attorney. The dedicated page on sending a letter of authority covers how to write one.

A letter of authority is not always enough

Not every organisation treats these documents the same way. Some organisations have different policies for dealing with a third-party authority, and some may not accept a general letter of authority at all; in that case the organisation's own third-party mandate form is what it asks for¹⁵. This is why a helper can find themselves able to speak to one firm about an account but blocked by another: the permission is granted by each organisation individually, on its own terms, and it does not carry across the market.

Scope also notes that mandates are usually only for a short amount of time¹, so a letter or mandate that satisfied a firm last year may not satisfy it this year. Firms refresh their checks because their duty is to the account holder: releasing information to the wrong person is a data breach, and letting an unauthorised person act is a fraud risk. A helper who is refused should ask the firm what form it needs, whether it needs the account holder to sign something specific, and whether the account holder needs to confirm capacity or identity.

The practical lesson is to check before you need it. If someone helps you with several accounts, ask each provider what it accepts, and keep a note of what permission is in place with each. Where a firm will not accept a letter or mandate at all, a registered power of attorney is the document that carries legal weight across providers, and the page on registering a power of attorney with a bank explains that process.

Setting up a mandate: how to apply

Setting up a mandate is free. The person being helped fills in a form giving permission to manage their account, which is known as a third-party mandate, and most banks have a third-party mandate form on their website³. The account holder's signature is the essential ingredient: you need permission from the person to get a third-party mandate, and it cannot be arranged without them⁴. nidirect's guidance for people with dementia describes the same step, setting up a third-party mandate that gives someone else access to your bank account, with you specifying how much access to give².

Each bank runs its own process, so expect some variation. Some ask the account holder to attend a branch or verify identity by phone or app; some ask the nominated person to provide identification too. The bank then decides whether to accept the mandate, and it does not have to agree⁶. Scope's guidance is that all banks should offer this arrangement⁴, and official guidance confirms that most banks, building societies and other account providers allow a third party access to your account, for example with a second card¹⁸. If your bank does not offer what you need, ask about its alternatives, including the extra support options described on our page about letting someone act for you.

Two related arrangements show how providers apply their own rules. If you nominate someone to collect your State Pension for you, most account providers allow a third party access to your account, for example with a second card¹⁸. And where money is to be paid out to someone else's account, providers set their own conditions: NS&I, for example, states that your nominated bank account must be a personal UK bank account, in your own name¹⁹. Separately, if you want money held by a court transferred into someone else's account, you will need to go to court to get approval²⁰. The pattern is consistent: the account holder's own name and permission anchor the arrangement.

Mental capacity: when a mandate works and when it ends

A third-party mandate only works while the account holder has mental capacity. Official guidance is explicit: if you have the right to handle the account of someone who has mental capacity, you have a third-party mandate, and it is not appropriate if the account holder is losing the ability to make relevant decisions themselves²¹. Which? states the rule bluntly: third-party mandates end when the account holder loses mental capacity⁵. Macmillan's guidance for people sorting out their affairs adds that the mandate should stop working immediately if you lose your mental capacity²².

This is the single most important limit on a mandate, and it catches families out. A mandate is a fine solution for someone who is physically frail, in hospital, or simply wants help, but who can still understand and give permission. Scope warns that mandates are not suitable if you are losing the ability to make your own decisions¹. The reason is structural: the mandate's authority flows from the account holder's ongoing consent, so when that consent can no longer be given or withdrawn, the permission has no foundation. The bank cannot keep relying on a signature given by someone who can no longer confirm it.

There is also a duty to keep the bank informed. Macmillan notes that the person nominated in the third-party mandate must tell the bank as soon as possible if the account holder's condition changes²². In practice, that means the helper may be the person who has to tell the bank that capacity has been lost, at which point the mandate ends and the account is frozen for the helper until a power of attorney or a Court of Protection deputyship is in place. If that moment is foreseeable, arranging a lasting power of attorney in advance avoids a gap in which nobody can lawfully pay the bills. Our page on lasting power of attorney or deputyship explains what happens when no arrangement exists.

How long a mandate lasts, renewal and cancellation

Mandates are usually only for a short amount of time¹. Banks treat them as temporary permissions rather than permanent arrangements, and some will ask for the mandate to be renewed, or the account holder's signature refreshed, after a period. Because each bank sets its own process, ask yours directly how long its mandate lasts and what it needs to renew one.

The account holder can withdraw permission at any time while they have capacity, since the mandate rests on their consent⁴. The bank should then remove the helper's access, and the timescale for how long a cancellation takes is set by each bank's own procedure. If the underlying account is being closed rather than just the mandate, any overdraft must be repaid first, and access to statements is lost once the account is closed⁷.

A mandate cannot be moved. You cannot transfer a third-party mandate to another account or bank⁴, so a switch means starting again with the new provider, including a fresh decision by the new bank on whether to accept it. And a mandate ends automatically, without anyone cancelling it, when the account holder loses mental capacity⁵ or dies. None of this is a reason to avoid a mandate, but it is a reason to keep its expiry date in mind: if the help is likely to be needed for years, or through a declining illness, plan the next arrangement before the mandate stops working.

A mandate is not a joint account

A third-party mandate keeps the account in one person's name. The bank account is still yours and does not become a joint account⁶. That distinction has real consequences. A joint account normally allows two or more people to receive payments, pay by debit card, transfer money and manage the account, depending on the bank²³, and joint holders typically own the money together and are each liable for the whole of any debt on it. A helper under a mandate has none of that ownership or liability: they act on your account, with your money, under your permission.

The difference shows up most clearly when things go wrong. On a joint account, if the holders fall out, either can ask the bank to register a dispute and cancel the mandate, freezing the account until everyone agrees how to split the money²³. A third-party mandate has no such shared control: the account holder can end the helper's access unilaterally, and the helper has no claim on the balance. The Current Account Switch Service works for joint accounts provided you are switching to another joint account and all account holders agree, and you can also switch a sole account to a joint account elsewhere²³, but a mandate cannot be transferred to another account or bank at all⁴.

Which arrangement suits a family depends on circumstances, and our comparison of a third-party mandate or joint account sets the two side by side. In short, a joint account makes the helper an owner, with everything that follows for debts, inheritance and disputes; a mandate makes them an agent, with access but no stake. For most people helping a relative temporarily, the mandate's lighter footprint is the point.

Mandate or Lasting Power of Attorney: which fits

The choice between a mandate and a lasting power of attorney (LPA) comes down to capacity, cost and time. A mandate is free, quick to arrange, and keeps the account holder in charge, but it ends the moment they lose mental capacity⁵ and the bank does not have to accept it⁶. An LPA is a legal document nominating someone to manage your affairs, and it is built for the opposite scenario: it is designed to keep working when you can no longer make decisions yourself.

The trade-off is set-up. NS&I's guidance notes that a Lasting Power of Attorney needs to be registered with the Office of the Public Guardian before it can be used, and that this can take up to 20 weeks to set up²⁴. A mandate can be in place in days. An LPA also costs money to register, whereas a mandate is free³. For someone who wants help now and has no reason to expect capacity problems, a mandate reaches that goal faster; for someone whose condition may progress, the LPA's long set-up is an argument for starting it early, not for skipping it.

The two can also sit alongside each other. A person with an LPA registered can still grant a mandate for convenience, and a family expecting decline often arranges the LPA first and uses the mandate meanwhile. A 2025 Which? investigation found some savings platforms do not allow third-party access, so donors may miss out on top rates, which is a reminder that access arrangements vary by provider whichever document you hold⁵. The fuller comparison, including what an attorney can and cannot do on an account, is on our pages comparing a third-party mandate with a power of attorney and explaining what an attorney can do.

Getting help

If a bank refuses a mandate, gets it wrong, or freezes an account after capacity is lost, there are places to turn. MoneyHelper offers free, impartial guidance on everyday banking, including opening, switching and closing accounts⁷. Citizens Advice can help with the underlying debt and benefits questions that often sit behind these arrangements. If a complaint to a bank about how it handled a mandate or a third-party request has stalled, the Financial Ombudsman Service can look at it, and our page on complaining for someone else explains how a helper raises the complaint.

For the capacity questions, the Office of the Public Guardian registers LPAs and oversees attorneys and deputies, and official guidance for attorneys and deputies dealing with banks is published by the government²¹. Our step-by-step guides cover making and registering a lasting power of attorney, powers of attorney in Scotland and in Northern Ireland, and becoming a deputy through the Court of Protection when no LPA exists. If someone is helping you with your money and you want to be sure the arrangement is safe, the page on keeping your bank account secure from an abuser covers the warning signs and what a bank can do.