Around one in four UK businesses will need to exit a commercial lease before the term ends, often because they’re relocating, downsizing, or selling up. That figure alone tells you how common assignment clauses are — and how many people get them wrong. I’ve watched business owners sign a lease, then realise a year later they need to move, only to discover the fine print locks them in or leaves them liable long after they’ve handed over the keys.
Over the years covering commercial property, the same pattern keeps coming up: tenants assume they can pass the lease to someone else and walk away clean. The reality is far more complicated. An assignment clause controls whether you can transfer the lease at all, what conditions the landlord can impose, and — critically — whether you stay on the hook after you leave. Here’s what you actually need to know.
If you’re thinking about moving premises or selling your business, the first thing to do is check your lease’s alienation clause. That’s the section that sets the rules. I’d also recommend reading our guide on understanding service charges in commercial leases, because those costs often complicate an assignment too. And if you need professional advice on the legal side, a tenant landlord lawyer can review your specific lease terms before you make a move.
What an Assignment Clause Actually Does
The most important thing to understand is that an assignment clause isn’t a simple “yes or no” switch. It’s a set of conditions. Some leases allow assignment only with landlord consent. Some allow it only if the new tenant meets specific financial criteria. And some prohibit it entirely. The clause itself dictates what you can and cannot do.
What I’d do before anything else: find the alienation clause in your lease and read it word for word. If it says “not to assign” without qualification, that’s an absolute prohibition — you cannot assign at all. If it says “not to assign without the landlord’s consent, such consent not to be unreasonably withheld,” that’s a fully qualified covenant, which is the most common type. That distinction matters because it determines your next move. For more context on how lease terms interact, our article on essential tips for a self-contained office lease covers related clauses you’ll want to understand.
Why Getting It Wrong Costs Real Money
The consequences of mishandling an assignment aren’t abstract. Under the Landlord and Tenant Act 1988, a landlord must respond to a consent application within a reasonable time and cannot unreasonably withhold consent. But “reasonable” is a slippery term. If your application is incomplete — missing financial references or details about the proposed assignee — the landlord can delay or refuse, and the clock doesn’t even start.
Here’s a scenario I see often: a tenant finds a buyer for their business, agrees a handover date, and then applies for landlord consent two weeks before completion. The landlord asks for three years of accounts from the assignee, bank references, and a rent deposit. The tenant scrambles, the assignee gets frustrated, and the deal collapses. The tenant is left paying rent on an empty unit for months.
That delay isn’t just inconvenient. It’s expensive. Rent, service charges, and insurance keep running. And if the lease has a break clause you’ve already missed, you’re stuck until the term ends. The difference between a smooth assignment and a costly mess is often just timing — applying early and having the paperwork ready.
What I’d do: apply for consent as soon as you have a serious prospective assignee, even before you’ve agreed final terms. The landlord can’t process what they don’t have. And if you’re dealing with a complex lease, a business lawyer can help you prepare the application so nothing is missing. Our piece on understanding tenant default terms also explains what happens if the assignee later fails to pay — a risk you need to factor in.
Where People Go Wrong With Assignments
I’ve seen the same mistakes surface again and again. They’re not about bad intentions — they’re about not knowing what the lease actually says and what the law requires. Here are the four most common ones.
Assuming You Can Assign Without Checking the Clause First
This is the biggest one. Tenants find someone to take over the lease, shake hands, and then discover the lease prohibits assignment entirely. An absolute covenant — one that says “not to assign” with no exceptions — means you cannot transfer the lease at all. You’re stuck. The only way out is to negotiate a surrender with the landlord, which usually costs you.
Even if the lease allows assignment, it may have conditions you didn’t notice. Some leases require the assignee to have a minimum net worth or turnover. Others require you to clear all rent arrears first. If you don’t meet those conditions, the landlord can refuse consent, and the law backs them up.
Not Understanding the Authorised Guarantee Agreement (AGA)
An AGA is a document the landlord can require as a condition of consent. It means you guarantee the new tenant’s performance under the lease. If they default on rent, you pay. If they breach a repair covenant, you pay. You’re out of the premises but not out of the liability.
This catches a lot of people off guard. They think assignment means a clean break. In reality, many commercial leases require an AGA as standard. The landlord wants a backstop, and you’re it. The only way to avoid it is to negotiate its removal before you sign the original lease — which is hard to do if you didn’t know about it at the time.
Submitting an Incomplete Consent Application
The landlord needs information about the assignee: accounts, bank references, proposed use of the premises, sometimes a rent deposit. If you send an incomplete application, the landlord can ask for more information, and the “reasonable time” clock doesn’t start until they have everything. That can add weeks.
What I’d do: prepare a full application pack before you submit it. Include the assignee’s last three years of accounts, two professional references, a clear statement of the proposed use, and a completed application form if the landlord provides one. Don’t leave gaps. A complete application on day one is the fastest route to consent.
Signing the Deed of Assignment Incorrectly
The transfer is documented in a Deed of Assignment. In the UK, deeds have strict signing formalities. Companies must execute them correctly — usually by two directors or a director and the company secretary. Individuals need a witness. If the deed isn’t signed properly, it may not be enforceable, and the assignment could be invalid.
This is one of those areas where a small mistake has big consequences. An invalid deed means you’re still the tenant, still liable for rent, and the assignee has no legal right to be there. The landlord can treat them as a trespasser and you as a defaulting tenant. Getting the execution right is non-negotiable.
→ Scroll right to see all columns
| Mistake | What Happens | How to Avoid It |
|---|---|---|
| Not checking the alienation clause | Assignment may be prohibited or conditional | Read the clause before you find an assignee |
| Ignoring the AGA requirement | You remain liable after assignment | Negotiate AGA terms early or budget for the risk |
| Incomplete consent application | Delays or refusal from landlord | Submit full financials and references upfront |
| Incorrect deed execution | Assignment is invalid; you stay liable | Follow UK deed signing rules precisely |
If you’re unsure about any of these steps, a property lawyer can review your lease and the proposed assignment documents before you commit. It’s cheaper than cleaning up a mess later.
How to Handle a Lease Assignment Properly
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If you need to assign your lease, the process is straightforward when you know the steps. Here’s how to do it without the common pitfalls.
Step 1: Review the Alienation Clause and Prepare Your Application
Start with the lease. Find the alienation clause and note exactly what it says about assignment, consent, and conditions. Then gather everything the landlord will need: the assignee’s accounts, bank references, details of their proposed use, and any rent deposit or guarantee they’ll provide. Don’t wait until you have a signed deal — prepare the pack in advance.
What I’d do: create a checklist from the lease’s conditions and tick each one off before you submit. If the lease says the assignee must be “of sufficient financial standing,” get their accountant to confirm that in writing. If it requires a guarantor, have one lined up. The more complete your application, the faster the landlord can process it.
Step 2: Agree Commercial Terms With the Assignee
Before you apply for consent, agree the key terms with the incoming tenant: the assignment date, any premium being paid, how rent and service charge apportionments will work, and who pays the landlord’s legal costs (usually the outgoing tenant). Also agree what happens with dilapidations — if the premises need repairs, who handles them before the handover.
Put everything in writing. A simple heads of terms document signed by both parties is enough at this stage. It doesn’t need to be a formal contract, but it should be clear enough that neither side can later claim they misunderstood.
Step 3: Apply for Landlord Consent and the Licence to Assign
Submit your application in writing with all supporting documents. The landlord will review it and, if satisfied, grant a licence to assign. This is a legal document that records the landlord’s approval and sets out any conditions — for example, a time limit for completion or a requirement to pay outstanding sums first.
The licence to assign is not just a letter. It’s a binding agreement. If you don’t comply with its terms, the consent may be invalid. Make sure you read it carefully and meet every condition before you complete the assignment.
Step 4: Prepare and Execute the Deed of Assignment
The transfer itself is done through a Deed of Assignment. Because it’s a deed, the signing rules are strict. For a company, it usually needs to be signed by two directors, or a director and the company secretary. For an individual, a witness must be present and sign too. If the deed isn’t executed correctly, the assignment may not be legally effective.
What I’d do: ask your solicitor to prepare the deed and check the execution before anyone signs. A small error here can undo the entire transaction. If you’re handling it yourself, use a template from a reputable legal publisher and follow the signing instructions to the letter.
Step 5: Complete the Handover
On the assignment date, handle the practical handover: return keys and access fobs, hand over alarm codes, take meter readings, and notify service providers and insurers. Confirm any apportionment payments — rent and service charge paid in advance needs to be split fairly between you and the assignee.
Keep copies of everything: the signed deed, the licence to assign, the consent application, and any correspondence with the landlord. You may need them later if a dispute arises about what was agreed.
For a deeper look at how lease terms interact with other costs, our guide on ensuring service charge transparency covers another area where misunderstandings are common.
Frequently Asked Questions
Can the landlord refuse consent for any reason? ▾
What happens if I assign without consent? ▾
Does an AGA ever expire? ▾
Can I assign a lease that prohibits assignment? ▾
Who pays the landlord’s legal costs for the licence to assign? ▾
What’s the difference between assignment and novation? ▾
If you’re dealing with a complex lease or a reluctant landlord, a real estate lawyer can advise on your specific situation and help negotiate the terms of the licence to assign.
Sources and Further Reading
Tips for leasing a food court space in the UK — If you’re in retail or hospitality, this guide covers specific lease considerations for shared commercial spaces.
Understanding public market lease agreements in the UK — A useful companion piece if your premises is in a market or council-managed property.
Lease Assignment Explained: How It Works and What UK Businesses Should Check. Sprintlaw, 2024.
Assignments and Underlettings: Consent, Alienation Clauses and Practical Pitfalls Explained. Athi Law, 2024.
