Comfort Letters In The UK: Uses And Key Legal Risks

If you’re growing a business, raising finance, signing a new lease, or taking on a major contract, you might be asked to provide a comfort letter.

It can sound harmless (even reassuring), but comfort letters can create real legal exposure if they’re drafted loosely or if your team treats them as “just a formality”.

In this guide, we’ll walk through what comfort letters are in the UK, when businesses use them, what they typically say, and the key legal risks to watch for - so you can move deals forward without accidentally giving away more than you intended.

What Are Comfort Letters (And Why Do They Exist)?

A comfort letter is a written statement one party gives to another to provide reassurance about a business relationship or financial position - often where the writer does not intend to give a full legal guarantee.

They’re commonly used when the other side wants some extra confidence, but you (or a parent company, director, or shareholder) aren’t willing to sign a strict guarantee or indemnity.

Comfort Letter vs Guarantee: The Key Difference

In plain English:

• A guarantee is usually intended to be legally binding - if the borrower/tenant/customer defaults, the guarantor pays.
• A comfort letter is usually intended to be “supportive” rather than strictly enforceable - but this is where the risk comes in.

If the wording in a comfort letter goes too far, it may become enforceable as a contract, or at least expose you to claims for misleading statements, misrepresentation, or negligent misstatements.

And if what you really need is a formal risk allocation document, a comfort letter might be the wrong tool entirely (or the wrong tool without careful drafting). In those cases, businesses often use a proper Deed Of Guarantee And Indemnity instead.

Are Comfort Letters Legally Binding In The UK?

Sometimes yes, sometimes no - and it’s highly fact-specific. The challenge is that you may not control how the other side interprets the letter later (especially if the deal goes wrong).

Whether a comfort letter is binding will depend on:

• The wording (does it read like a promise or an intention?)
• The context (was it required as a condition of a loan, lease, or contract?)
• Reliance (did the recipient rely on the letter to enter the deal?)
• Whether it contains the elements of a contract (offer/acceptance/consideration, intention to create legal relations, certainty)

Even where a letter says “not binding”, “no intention to create legal relations”, or “no reliance”, those statements aren’t always determinative on their own - a court will look at the document as a whole and the surrounding circumstances.

If you’re unsure how “binding” a particular letter might look, it helps to understand what makes a contract legally binding - because comfort letters can drift into contract territory faster than you’d expect.

When Do UK Businesses Use Comfort Letters?

Comfort letters pop up in a few predictable scenarios for small and scaling businesses. The common theme is that someone wants reassurance, but the parties haven’t agreed to (or can’t obtain) a stronger form of security.

1) Bank Lending And Business Finance

Banks and lenders may request a comfort letter where:

• the borrower is a subsidiary or newly formed company with limited trading history
• the lender wants reassurance a parent company will support the borrower
• a director or shareholder is involved in discussions, but doesn’t want to give a personal guarantee

In practice, a lender might treat a comfort letter as part of the broader risk picture, alongside security documents, covenants, and sometimes a formal shareholder loan arrangement.

2) Commercial Leases (Landlords Want Reassurance)

If you’re taking a commercial lease through a limited company (especially a newco), landlords often look for comfort around rent payment and repairing obligations.

In many cases, landlords ask for:

• a rent deposit
• a guarantor (often a director or group company)
• or a comfort letter from a parent company

A comfort letter may be presented as a “lighter touch” alternative to a guarantee - but it still needs careful wording, particularly if it references future financial support.

3) Big Supplier Or Customer Contracts

If a larger customer is considering signing with your small business, they may worry about continuity and delivery risk.

They might ask your company (or your holding company/investor) for a comfort letter confirming things like:

• you have the resources to perform the contract
• you intend to keep supporting the delivery team
• you don’t plan to shut down the relevant business line mid-contract

Often, this sits alongside the main Service Agreement, which should set out the real rights and remedies if things go wrong (rather than relying on vague reassurance).

4) Corporate Transactions And Due Diligence

Comfort letters sometimes appear during:

• share sales or business acquisitions
• investment rounds
• group restructures

For example, you might see a comfort letter about the status of a subsidiary, ongoing funding plans, or the intention to maintain certain arrangements after completion.

Where contracts are being transferred between entities (for example, moving a contract from one group company to another), you’ll often need a formal legal mechanism like a Deed Of Novation rather than a comfort letter - because a comfort letter won’t actually transfer rights and obligations.

What Does A Comfort Letter Usually Include?

There isn’t one fixed “UK template” for comfort letters. They tend to be short, and that’s part of the danger: the shorter and vaguer they are, the more room there is for dispute.

That said, many comfort letters include some combination of the following:

• Relationship context (who is writing, and their connection to the company entering the deal)
• Awareness of the transaction (e.g. “we understand you are considering entering into…”)
• Statements about current intention (e.g. intention to support a subsidiary, maintain ownership, or ensure access to resources)
• Statements about current facts (e.g. current financial position, group structure, or funding arrangements)
• Limitations and disclaimers (e.g. not a guarantee, no intention to create legal relations, reliance limitations)
• Time limits (e.g. letter only valid for a defined period or for a specific transaction)

A Quick Reality Check: “Soft Language” Isn’t Always Safe

Many comfort letters rely on phrases like “it is our present intention” or “we expect” or “we will use reasonable endeavours”.

Those words can help signal the letter is not a strict guarantee - but they do not automatically eliminate legal risk.

If the recipient relies on the letter and suffers loss, the dispute often becomes about:

• what the writer reasonably meant in the circumstances
• what the recipient reasonably understood
• whether the statements were accurate and responsibly made

Key Legal Risks With Comfort Letters (What Can Go Wrong?)

Comfort letters are often signed quickly to keep a deal moving. That’s exactly when problems happen.

Here are the main risk areas to be aware of as a UK business.

1) Accidentally Creating A Binding Obligation

If a comfort letter is drafted in a way that looks like a promise - for example, “we will ensure the subsidiary meets its obligations” - it can start to resemble a guarantee.

Even if you label it a “comfort letter”, a court will look at substance over title.

Practical tip: a sentence that feels “reassuring” in a negotiation can become a hard obligation later. If the other side is relying on it to proceed, treat the wording like it matters (because it does).

2) Negligent Misstatement (Saying Something Inaccurate)

A major comfort-letter risk isn’t just contract law - it’s making statements that turn out to be wrong.

If you state something about finances, funding, group support, or plans, and that statement was made carelessly (or without proper checks), the recipient may argue:

• they relied on the statement, and
• they suffered loss when it turned out not to be true.

This is where comfort letters can be particularly risky for directors or parent companies, because recipients may claim they reasonably relied on a statement given the writer’s position and involvement.

3) Misrepresentation Risk (Inducing The Other Side Into The Deal)

If your comfort letter includes a statement of fact that is false and it induced the recipient to enter the transaction, this can raise misrepresentation issues (which can lead to damages and/or attempts to unwind the transaction in some cases).

Small businesses get caught here when they:

• overstate revenue or cash runway
• suggest investor support is “committed” when it’s only being discussed
• imply the parent company will fund losses without internal approval

This is why it’s important that comfort letters align with your actual legal documents and approvals - not just what you hope will happen.

4) Director Duties And Insolvency Pressure

If you’re a director signing (or authorising) a comfort letter that implies ongoing financial support, be careful if the company (or group) is under financial stress.

When a company is approaching insolvency, directors have heightened responsibilities and need to avoid worsening creditor positions. A comfort letter that implies support, funding, or “no matter what” backing can create:

• commercial pressure to keep funding beyond what’s realistic
• disputes about what the business committed to
• risks if the business later stops support and the counterparty claims they relied on it

Even where you can support a subsidiary, it’s still worth keeping any comfort-letter wording tight, accurate, and approved internally.

5) Group Company Risk (Cross-Contamination Of Liability)

Many comfort letters are issued by a parent company to support a subsidiary.

That can be commercially sensible - but from a risk perspective, you want to avoid turning a problem in one entity into a claim against the whole group.

This is especially important where you’ve structured your business for limited liability. If a comfort letter effectively gives a third party a pathway to pursue the parent, you may be undermining that risk separation.

How To Use Comfort Letters Safely: A Practical Checklist

Comfort letters aren’t “bad”. They’re a common tool in business deals - you just need to approach them like a legal document, not a friendly email.

Here are practical steps you can take to reduce your risk.

1) Be Clear About The Commercial Purpose

Before drafting anything, get clarity on what the other side is actually trying to achieve. Ask:

• Are they looking for comfort about performance or delivery capability?
• Are they looking for financial backing?
• Are they trying to replace a guarantee with softer wording?

Once you know the goal, you can decide whether a comfort letter is appropriate or whether another document is needed.

2) Decide Early: Do You Want It Binding Or Not?

This sounds obvious, but comfort letters often become a muddle because each side assumes something different.

• If you do want a binding promise (for example, you’re willing to stand behind a subsidiary), it may be cleaner to use a formal guarantee or indemnity.
• If you don’t want it binding, the drafting needs to consistently reflect that position (and the overall context needs to support it too).

3) Keep Statements Factual, Verifiable, And Narrow

Where possible, stick to statements you can verify today, rather than broad promises about the future.

For example, “we currently hold 100% of the shares” is easier to stand behind than “we will ensure the company can pay all liabilities as they fall due”.

4) Avoid “Guarantee-Like” Phrases Unless You Mean It

Be cautious with language such as:

• “we will ensure”
• “we guarantee”
• “we will pay”
• “we undertake”

Even “reasonable endeavours” language can create arguments about whether you did enough, depending on the context.

5) Use Limitations (But Don’t Treat Them As Magic Words)

Many comfort letters include wording like:

• the letter is not a guarantee
• no intention to create legal relations
• no reliance except for a specific purpose
• limited to a specific transaction and timeframe

These clauses can help, but they need to be coherent with the rest of the letter. If you include a “not binding” paragraph and then make a strong promise in the next paragraph, the “not binding” part may not save you.

6) Get Internal Approvals (And Align With Your Other Documents)

Comfort letters often create hidden governance issues, particularly in:

• company groups
• businesses with external investors
• companies with multiple directors

Make sure the comfort letter aligns with:

• board approvals (where needed)
• funding agreements or investor documents
• your constitutional and shareholder arrangements

For example, if investor consent is needed for certain undertakings, or if there are restrictions on financial support between companies, you’ll want to catch that early - often by checking your Shareholders Agreement before anything is issued.

7) Consider Whether A Different Document Fits Better

Depending on the deal, a comfort letter may be the “wrong shape” for what you need. Common alternatives include:

• Guarantee/indemnity (where the other side needs real payment security)
• Contract variation (if you’re changing obligations in an existing agreement)
• Novation (if a contract is being moved to another entity)
• Term sheet / heads of terms (if you’re still negotiating and need a clear non-binding framework)

Where the parties are at an early stage and want to map out the deal before full contracts, it may be better to document the commercial understanding in a Term Sheet rather than using a comfort letter for something it’s not designed to do.

Key Takeaways

• A comfort letter is used to provide reassurance in a deal - often where the other side wants extra confidence but you don’t want to sign a strict guarantee.
• Comfort letters can be risky because poorly drafted wording may create a binding obligation or expose you to claims for misrepresentation or negligent misstatement.
• Common scenarios include lending/finance, commercial leases, major supplier or customer contracts, and corporate transactions.
• To reduce risk, keep comfort letters narrow, accurate, and consistent - and avoid “guarantee-like” promises unless you genuinely intend to take on that liability.
• Comfort letters should fit within your broader legal setup (including approvals and shareholder arrangements), and sometimes a different document (like a guarantee or novation) is the better tool.

If you’d like help drafting or reviewing a comfort letter (or working out whether you should be using a different document altogether), you can reach us at 08081347754 or team@sprintlaw.co.uk for a free, no-obligations chat.