Over the past few years, I’ve watched countless business owners get stuck in leases they no longer need. The numbers back up what I see: average office lease lengths in the UK have actually increased by 27% between 2023 and 2024, climbing from 2.9 years to 3.7 years. That might sound like stability, but for a tenant whose business has outgrown its space — or shrunk — those extra months can feel like a trap. The good news is that you don’t have to stay stuck. Transferring your lease to someone else is a legal process called assignment, and when done right, it lets you walk away cleanly.
But here’s the thing — assignment isn’t as simple as handing over the keys. The legal process is precise, and one misstep can leave you on the hook for rent long after you’ve moved out. I’ve covered commercial property long enough to know that the questions people ask most often aren’t about the theory — they’re about the practical steps, the paperwork, and what happens when the landlord says no. If you’re thinking about renting a commercial space or trying to get out of one, here’s what you actually need to know.
What Assigning a Commercial Lease Actually Means
Let’s get the definition out of the way quickly, because the real insight is in what it means for you. Assigning a lease means transferring your entire interest in the property to someone else. You step out, they step in. Unlike subletting — where you stay on as the tenant and create a separate arrangement — assignment replaces you entirely. The new tenant takes over rent, repairs, and all the covenants in the original lease.
What I notice most often is that people assume assignment is a clean break. It can be — but only if you handle the paperwork correctly. The key document is a deed of assignment, which formally transfers the lease. For registered leases over seven years, you’ll also need Land Registry Form TR1. For shorter leases, a standalone deed works. Either way, the deed must include the lease details, the transfer date, and the assignee’s agreement to take on all obligations from that point forward.
Why Getting This Right Matters More Than Ever
The commercial property market is shifting fast. Investment demand surged 28% in Q4 2024 compared to the previous year, which means more buyers and tenants are looking for space. That’s good news if you’re trying to find someone to take over your lease — but it also means landlords are being more selective about who they approve.
Here’s a scenario I see play out regularly: a small business owner signs a five-year lease, then six months in realises the space is too big. They find a willing assignee, but the landlord drags their feet on consent. Under the Landlord and Tenant Act 1988, the landlord must respond within a reasonable time — typically 14 days — and can’t unreasonably withhold consent. But if the assignee doesn’t meet the landlord’s financial criteria, the whole thing falls apart. The original tenant is left paying rent on an empty unit.
What I’d do in that situation is prepare the assignee’s financials before approaching the landlord. Have bank statements, accounts, and references ready. It speeds up the process and shows the landlord you’re serious. If you’re unsure about the legal steps, speaking with a tenant landlord lawyer early can save you months of stress.
Where Most People Get Stuck
Over the years, I’ve seen the same mistakes crop up again and again. Here are the four that cause the most trouble — and how to avoid each one.
Assuming Consent Is Automatic
This is the biggest one. Many tenants think that because they’ve found a willing assignee, the landlord has to say yes. That’s not how it works. The landlord can refuse if the assignee doesn’t meet reasonable criteria — like having a strong credit history or sufficient trading record. If you skip the consent step entirely, the assignment is invalid, and you remain liable for everything.
Missing the Authorised Guarantee Agreement
For commercial leases signed after 1995, landlords often require an authorised guarantee agreement (AGA). This document makes you guarantee the new tenant’s performance for the rest of the lease term. If they default, the landlord can come after you. I’ve seen business owners caught out by this years after they thought they were free. My advice: negotiate for a full release from the AGA when you assign. Some landlords will agree, especially if the assignee is financially strong.
Ignoring the Upcoming Law Changes
The legal landscape is about to shift. The government’s English Devolution and Community Empowerment Bill, published in July 2025, proposes banning upward-only rent reviews in new and renewal commercial leases. That means future rent could go down as well as up — which is good for tenants but could affect how landlords value leases. If you’re assigning a lease now, the terms the new tenant takes on might look very different in a couple of years.
Overlooking the Service Charge Code
The updated RICS Professional Standard on service charges in commercial property took effect from 31 December 2025. While it’s not legally binding, it sets industry benchmarks for how service charges are calculated and disputed. If your lease has complex service charge provisions, the new code could affect what the assignee is expected to pay. Make sure you disclose all service charge information upfront — it’s a common sticking point in negotiations.
→ Scroll right to see all columns
| Change | Expected Date | Impact on Lease Assignment |
|---|---|---|
| Ban on upward-only rent reviews | Late 2026 / 2027 | New assignees may benefit from lower future rents |
| EPC rule changes | Second half of 2026 | Assignees may need to fund energy upgrades |
| Business rates revaluation | 1 April 2026 | New five-tier multiplier could change occupier costs |
| Security of tenure reform | Ongoing consultation | Minimum lease term may increase to 2 years |
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How to Assign Your Commercial Lease: A Practical Guide
If you’ve decided to assign, here’s the step-by-step process I’d follow. Each stage has its own pitfalls, so take your time and get the paperwork right.
Check Your Lease for Restrictions
Before you do anything, read your lease. Look for the clause on assignment — it will tell you whether you need landlord consent and what conditions apply. Most commercial leases require consent, but the wording matters. Some leases say consent “shall not be unreasonably withheld,” which gives you some protection. Others are more restrictive. If you’re unsure, a property lawyer can review the lease and advise on your options.
Find a Suitable Assignee
The assignee needs to be someone the landlord will approve. That usually means a business with a strong financial track record, good credit, and a solid trading history. If you’re struggling to find someone, consider using a commercial property agent or listing the lease on a specialist marketplace. Be upfront about the lease terms — including the rent, service charges, and any upcoming repairs — so the assignee knows what they’re taking on.
Prepare the Documentation
You’ll need three key documents: a deed of assignment, a licence to assign (the landlord’s formal consent), and possibly an authorised guarantee agreement. The deed transfers the lease. The licence to assign confirms the landlord’s approval. The AGA, if required, makes you guarantee the assignee’s performance. Each document must be drafted correctly and signed by all parties. A solicitor can prepare these for you, or you can use a specialist legal service. If you’re looking for a business lawyer to handle the paperwork, it’s worth getting a fixed fee quote upfront.
Submit the Consent Request
Once you have the assignee’s details and financials, submit a formal consent request to the landlord. Include the proposed assignee’s name, business details, accounts, and references. The landlord has a duty to respond within a reasonable time — typically 14 days — and cannot unreasonably withhold consent. If they refuse, ask for written reasons. You may be able to challenge the refusal if it’s unreasonable.
Complete the Transfer
After the landlord gives consent, sign the deed of assignment and the licence to assign. If the lease is registered, file Form TR1 with the Land Registry. Notify the landlord in writing that the assignment is complete. From that point, the assignee takes over all obligations — but remember, if you signed an AGA, you’re still on the hook if they default.
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1Check Your LeaseFind the assignment clause and note any restrictions or conditions on consent.
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2Find a Suitable AssigneeLook for a tenant with strong financials and a solid trading history to maximise landlord approval.
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3Prepare DocumentsDraft the deed of assignment, licence to assign, and any required authorised guarantee agreement.
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4Submit Consent RequestSend the assignee’s financials and details to the landlord and wait for written approval.
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5Complete the TransferSign all documents, file with Land Registry if needed, and notify the landlord in writing.
What About the Upcoming Changes?
The law is moving in a tenant-friendly direction. The proposed ban on upward-only rent reviews could make leases cheaper for assignees in the long run, which might make your lease easier to pass on. But there’s a catch: the same bill also proposes widening the definition of Assets of Community Value to include properties that contribute to economic wellbeing. That could affect how quickly a landlord can sell or redevelop a property after an assignment. Keep an eye on the progress of the English Devolution and Community Empowerment Bill — it’s at committee stage in the House of Lords as of early 2026, and could become law by late 2026 or 2027.
Frequently Asked Questions
Can I assign a lease if the landlord refuses consent? ▾
What happens to my rent deposit when I assign? ▾
Do I need a solicitor to assign a commercial lease? ▾
Can I assign a lease that has less than a year left? ▾
What’s the difference between assignment and subletting? ▾
If you’re thinking about assigning your commercial lease, the most important step is to start early. Give yourself time to find the right assignee, prepare the paperwork, and negotiate with the landlord. The market is active — investment demand is up, and lease lengths are stabilising — but the legal process still demands care. Get the documents right, understand your ongoing liability, and don’t be afraid to ask for professional help. If this was useful, you might also want to read The Hidden Costs of Commercial Renting in the UK: Are You Prepared?
Sources and Further Reading
Commercial Property Rental Checklist — A practical checklist to help you prepare before signing any commercial lease agreement.
Service Charges Explained — A breakdown of how service charges work in UK commercial leases and what tenants should watch for.
Assigning a Lease UK: Complete Legal Process 2026. Connaught Law, 2026.
A Practical Guide to Upcoming Commercial Property Law Changes in 2026. Longmores Solicitors, 2026.
UK Real Estate Sector 2026 and Beyond. Charles Russell Speechlys, 2026.
