A missing Court of Protection rule can stop a bank, building society or NS&I from releasing money, even when the savings belong to someone who has lost mental capacity. That can turn a simple transfer, withdrawal or new account opening into a delay, with paperwork rejected and routine access blocked.
If you are a deputy or acting under the Court of Protection, the key question is not just whether an ISA or Premium Bonds are allowed, but which is easier to access, document and manage for the person’s needs. The right choice depends on liquidity, risk, tax treatment, and whether the money is needed soon, later, or kept for safety.
What authority you need before acting
Deputyship & Court of Protection: Managing ISAs vs Premium Bonds starts with one simple rule: the provider must accept your legal authority before it moves a penny.
Deputyship versus lasting power of attorney
A deputy acts under a Court of Protection order when a person no longer has capacity to manage their own affairs. That is different from a Lasting Power of Attorney, which the person signs while they still understand what they are doing.
The difference matters because banks and NS&I do not treat both routes the same way. A deputy usually needs a sealed order, identity evidence, and sometimes a provider-specific form before it can touch the account.
Court of protection orders and scope
The Court of Protection can give a deputy wide powers or narrow ones. A finance order may allow day-to-day savings work, but not every order covers every transaction.
A common mistake is to assume the title “deputy” unlocks everything. It does not. The paperwork must match the job.
The provider decides whether your order is enough for that specific request, so the same deputyship can work for one bank and stall at another.
Office of the public guardian records
The Office of the Public Guardian keeps records of deputies and checks how they act. That is why clear notes matter from the first phone call.
Keep copies of every letter, form, and call note.
Most providers ask for the order, photo ID, proof of address, and account details. Some also want certified copies, not plain scans.
A safe working rule is this: if the account already exists, expect checks before access. If the account is new, expect more checks and more time.
In practice, the route you use can matter almost as much as the legal authority itself. Many providers will let a deputy start the process by phone, because that is usually the fastest way to confirm what documents they need and whether the Court of Protection order is enough for the request. However, identity checks often still have to be completed by post, especially where certified copies are required. Online access is more limited: some NS&I services can be used online once the deputyship has been verified, but new registrations, account changes or cash-ins may still need a paper trail first.
For example, a deputy may be able to ask for information by phone, then send a sealed order and certified copies by post before any transfer is released. That distinction is important for savings access because a process that looks digital on the surface may still depend on manual checks behind the scenes.
How ISAs work after incapacity
An ISA can still be managed after the person loses capacity.
ISA allowance and subscriptions
The ISA allowance stays available to the person, but the money must still be added in the right way. A deputy can usually make subscriptions from the person’s own funds if the provider accepts the authority.
For the 2024/25 tax year, the overall ISA allowance is £20,000.
The key point is this: the allowance belongs to the person, not to the deputy. The deputy acts only for that person’s benefit.
ISA subscriptions must follow the provider’s authority process, even when the allowance is still available.
Transfers, replacements and cash ISAs
A cash ISA is often the simplest option when money may be needed soon. It works like a locked envelope that keeps interest tax-free, while still being easier to explain than some investments.
HM Revenue and Customs does not usually need a special “deputy ISA permit”. The deputy still needs to keep the account within ISA rules and keep the records neat.
Keep note of dates, amounts, and the reason for each move.
The tax position also deserves a fuller comparison. A cash ISA can shelter interest or growth from income tax and capital gains tax within the ISA rules, but the ISA allowance remains a personal allowance and must be used correctly even when the person lacks capacity. That means a deputy can normally continue or make ISA subscriptions from the person’s own funds, provided the provider accepts the authority and the subscription is otherwise valid. Bonds sit outside the ISA system entirely: they do not use ISA allowance, and any prizes are tax-free prizes rather than interest.
For someone under deputyship, that difference matters because the ISA may be better for predictable tax-free saving, while Premium Bonds may suit spare cash where the priority is capital security and occasional prize chance rather than regular return.
How premium bonds work for a deputy
Premium Bonds are not a savings account with interest.
Tax-free prizes, not interest
Premium Bonds pay tax-free prizes instead of interest. That means the holder may win nothing in a month, or may win a larger prize by chance.
The return is uncertain, so this product suits money that can sit still.
NS&I access and identity checks
NS&I often asks for its own authority route before a deputy can manage Premium Bonds.
The phrase NS&I Power of Attorney online sounds easy, but the practical path often starts offline first.
Buying more bonds or cashing in
A deputy can usually ask NS&I to cash in bonds if the order and identity checks are in place. Buying more bonds is different, because new purchases may need a fresh authority check.
A deputy should also remember that Premium Bonds have a minimum holding period before cashing in.
Premium Bonds can suit spare cash that the person is unlikely to need soon.
The practical view is plain: use Premium Bonds for dormant cash, not for money with a date on it.
ISA versus premium bonds in practice
The choice comes down to purpose.
Comparison table: access, risk, tax
| Feature |
ISA |
Premium Bonds |
| Return |
Interest or investment growth, depending on the ISA type |
Tax-free prizes, but no guaranteed return |
| Access |
Often flexible, especially in cash ISAs |
Cash-in is possible, but prize income is uncertain |
| Tax treatment |
Usually tax-free within ISA rules |
Prizes are tax-free |
| Best for |
Money that may be spent, transferred, or held with planned access |
Money that can stay untouched for longer |
Liquidity for near-term spending
Liquidity means how quickly cash can be turned into spending money.
If the person needs care costs, utility bills, or home repairs soon, a cash ISA is usually easier to use.
Best for emergencies or long-term
Emergency money should behave like emergency money.
Money with a job should not sit in a product that pays by luck.
As a rule, use the ISA for planned spending and Premium Bonds for spare cash that can wait.
Capital preservation versus prize chance
An ISA usually gives a steadier picture of what the money is doing. Premium Bonds give a prize chance instead.
Practical steps for deputies
The best results come from a simple checklist.
Step 1: confirm authority
Check the Court of Protection order or the power of attorney document. Then confirm that the provider accepts it for the action you want to take.
Step 2: identify the product and account
Write down the account number, provider name, and current balance.
Use the provider’s deputyship or authority team if it has one.
Step 4: record every decision
Keep a short log of what was requested, why it was needed, and who agreed it.
Step 5: review whether the money still fits the person’s needs
A cash need can change quickly.
Best-interests decisions should be reviewed whenever the person’s spending needs change.
If the person still has capacity and manages their own savings, this deputyship process does not apply, and a standard ISA versus Premium Bonds comparison is enough.
A sensible working checklist helps avoid delays. First, confirm whether the person has a lasting power of attorney or whether you are acting under a Court of Protection deputyship order. Next, check the exact product: a cash ISA may allow subscriptions, transfers or withdrawals, while Premium Bonds may need a separate NS&I authority check. Then gather the usual documents: the sealed order or certified copy, proof of identity, proof of address and the account number. If the goal is to open a new account, ask whether the provider accepts applications from a deputy at all, because some will only allow management of an existing holding.
If the goal is to transfer money, check whether the transfer would affect the person’s access needs or tax position. A short call to the provider’s specialist team often saves days of rejected forms, because it clarifies whether the request can be made online, by phone or only by post.
Common mistakes that cause delays
The biggest delays usually come from bad assumptions, not bad law.
Assuming online access works first time
Do not assume the provider will accept an online form on day one.
Treating premium bonds like cash
Premium Bonds are not a steady savings pot.
Forgetting to match the product
If the money pays for care, use the product that supports predictable access.
The product should follow the money’s purpose, not the other way round.
Frequently asked questions
Do premium bonds count towards your ISA allowance?
No, they do not. Premium Bonds sit outside the ISA system, so they do not use any ISA allowance. That means a deputy can hold both products for the same person, but each one follows its own rules. The key is still authority, purpose, and record-keeping.
Can a deputy cash in premium bonds online?
Sometimes, but not always straight away. NS&I often wants authority checks before online changes go through. If the deputyship is not already registered, the safer route is usually phone or post first, then online later if NS&I allows it.
What documents are needed to manage an ISA or Premium Bonds?
Usually the sealed Court of Protection order or power of attorney document, photo ID, proof of address, and the account details. Some providers also ask for certified copies. The exact list depends on the firm, so the first call should ask for its deputyship team or authority process.
Is there tax to pay on premium bonds prizes?
No, Premium Bonds prizes are tax-free. That is one reason many families like them. The catch is simple: tax-free does not mean guaranteed income, so they still need a careful fit with the person’s cash needs.
Can a deputy open a new ISA for someone who lacks capacity?
Often yes, but only if the provider accepts the deputy’s authority and the order allows the action. The person’s allowance still exists, but the provider may want extra checks before a new account opens. That is where the form and evidence trail matter most.
Does the court of protection have to approve every change?
Not always. Many routine savings decisions sit within a deputy’s powers, as long as they stay within the order and the person’s best interests. Bigger or unusual moves may need more care, and sometimes a fresh court application.
What to do next
Start with the money’s purpose, then choose the product that fits it.
If the money can sit untouched, Premium Bonds may suit, but only when the deputy accepts the uncertain return.
Keep the records short, clear, and dated. That habit saves time, and it keeps the deputy on the right side of the Court of Protection rules.
Which is better for someone under court of protection?
There is no single winner. An ISA usually fits planned spending and steadier access, while Premium Bonds fit spare money that can wait. The better choice is the one that matches the person’s need, risk tolerance, and timing.
