Sending a mate £30 for your share of a curry is one thing. Transferring £25,000 to a sibling for a house deposit is something else entirely — yet millions of people use the same tool for both. Faster Payments, bank transfers, and apps like Monzo or PayPal make moving money frictionless. That frictionlessness is exactly the problem. When the sums get large, the absence of legal scaffolding around an instant transfer can cost you the money, the relationship, and — in the worst cases — a significant chunk of your tax position. If you’re about to lend or receive a five-figure sum from family or friends, the next few minutes of reading could save you from a genuinely ruinous mistake.
An Instant Transfer Is a Pipe, Not a Contract
Every payment app and bank transfer service is designed to do one job: move money from account A to account B as quickly as possible. It has no opinion on why the money is moving. There is no mechanism to record repayment terms, interest rates, default triggers, or what happens if the borrower dies. The reference field — “loan for flat deposit” — carries roughly the same legal weight as a Post-it note stuck to a fridge.
Courts in England and Wales will look at a large, undocumented transfer and ask a simple question: was this a gift or a loan? The burden of proving it was a loan falls on the person who sent the money. Without a signed written agreement, you are left assembling WhatsApp messages, vague emails, and your own testimony. That is not a legal strategy; it is a scramble. A formalised peer-to-peer lending arrangement — whether through a dedicated platform or a properly drafted loan agreement — creates the evidence at the point of transfer, not after things have gone wrong.
The Gift Trap: HMRC, IHT, and CGT
HMRC does not need to believe your story. It needs documentation. A large transfer without a loan agreement is presumed to be a potentially exempt transfer (PET) for Inheritance Tax purposes. If the lender dies within seven years, that sum could be pulled back into their estate and taxed at 40 per cent above the nil-rate band. Worse, if the “borrower” has been making repayments informally, HMRC may treat those repayments as separate gifts flowing in the other direction, creating a tax mess on both sides.
Capital Gains Tax adds another layer of complexity. If the money helped purchase a property that is not the borrower’s sole or main residence, any gain on disposal is chargeable. If unequal contributions were made but no Declaration of Trust exists to record beneficial interests, HMRC will default to equal ownership — meaning CGT liabilities may land on the wrong person. Principal private residence relief only covers the period and proportion during which the property was genuinely the owner’s main home. Get this wrong and you could face a five-figure tax bill that proper documentation would have eliminated.
Family Court, Divorce, and the Disappearing Loan
When a couple divorces, the court divides the matrimonial asset pool. An undocumented transfer from a parent to their child’s spouse is almost invariably treated as a gift to the couple — meaning half of “your” money walks out the door with the ex. A formal loan agreement, ideally executed as a deed (which carries a 12-year limitation period rather than six years for a simple contract), registers the sum as a liability on the borrower’s financial statement. That liability reduces the asset pool. The difference can be tens of thousands of pounds.
This is not theoretical. The case law is littered with parents who transferred house-deposit money via bank transfer, assumed everyone understood it was a loan, and watched a judge classify it as a gift because no contemporaneous written agreement existed.
Co-Ownership and the Risks Most People Never Consider
Large informal transfers frequently fund property purchases between friends, siblings, or unmarried partners. If you are buying property with someone else, you need to understand several hard realities that no payment app will warn you about:
- Joint and several liability: On a joint mortgage, the lender can pursue either borrower for 100 per cent of the outstanding debt — not just their “half.” If your co-buyer stops paying, you owe the lot.
- Future mortgage capacity: Lenders stress-test each borrower against the full mortgage debt. A co-buyer wanting to purchase their own home later may find they simply cannot qualify.
- SDLT surcharge: If either co-buyer already owns property anywhere in the world, the 3 per cent higher rate of Stamp Duty Land Tax applies to the entire purchase price. This routinely blindsides first-time buyers who team up with a friend who owns a buy-to-let.
- Tenancy in common vs joint tenancy: Non-married co-buyers should almost always hold as tenants in common, allowing unequal shares and independent inheritance rights. Joint tenancy forces automatic survivorship — your share passes to the other owner on death, regardless of your will.
- TOLATA 1996: Either co-owner can apply to court to force a sale of the property, even if the other refuses. Without a co-ownership agreement setting out a buy-sell mechanism and exit timeline, you could be dragged into expensive litigation with no agreed framework for resolution.
A Declaration of Trust (Deed of Trust) is not optional in these situations — it is essential. It records beneficial interest percentages, specifies whether unequal contributions are treated as loans or equity adjustments, and sets out what happens on sale. Without one, courts and HMRC default to equal shares regardless of who actually paid what.
What a Proper Lending Agreement Actually Looks Like
Whether you use a peer-to-peer lending platform or instruct a solicitor, the agreement should cover — at minimum — the following:
- Principal amount and date of advance
- Interest rate (even if zero — state it explicitly so HMRC cannot imply one)
- Repayment schedule: frequency, amounts, and method
- Maturity date: when the loan must be fully repaid
- Default provisions: what constitutes default and what remedies are available
- Security: whether the loan is secured against an asset (a second charge on property, for instance)
- Early repayment terms
- Signatures of both parties, witnessed
Execute it as a deed if possible. The 12-year limitation period gives you double the enforcement window of a standard contract — and for sums that may not come due for years, that extra time matters enormously.
The Relationship Argument Is Backwards
People avoid formal agreements because they feel “uncomfortable” or think it signals distrust. This is backwards. Ambiguity is what destroys relationships. When both parties have signed a clear document, there is nothing to argue about — the terms are on paper. When there is no document, every late repayment becomes a silent grudge, every family gathering becomes tense, and every financial setback becomes a potential betrayal. A written agreement is not the opposite of trust; it is trust made durable.
What to Do Before You Hit “Send”
If you are about to transfer a large sum to a family member or friend, pause and take these concrete steps. First, instruct a solicitor to draft a loan agreement — or, if property is involved, a Declaration of Trust — executed as a deed. Second, ensure both parties take independent legal advice so neither can later claim they did not understand the terms. Third, set up repayments via standing order to a dedicated account, creating an unambiguous paper trail. Fourth, notify your accountant or tax adviser so the transaction is correctly reflected in both parties’ tax affairs. Finally, if the money is funding a property purchase, confirm the SDLT position before exchange — discovering a surprise surcharge at completion is both expensive and avoidable. The transfer itself takes seconds. The preparation that protects it should take considerably longer.
Disclaimer: The information provided in this article is for informational purposes only and should not be considered financial or legal advice. Property and lending laws in the United Kingdom vary and may change over time. We always recommend consulting with a qualified solicitor and mortgage broker before entering into a property purchase or financial arrangement with another party.
