Who Is Really Behind the Counter? A Landlord's Guide to Unauthorised Subletting

The rent arrives on time. The shop front looks presentable. Yet the person behind the till on a Tuesday is not the tenant named on the lease — and nobody told you. Unauthorised subletting is one of the most common breaches of commercial leases in England and Wales, and one of the most frequently overlooked. For landlords of shops, offices and industrial units, understanding how to respond calmly and lawfully can make the difference between a swift resolution and a costly piece of litigation.

Why Tenants Sublet Without Asking

The motives are rarely sinister in the way landlords imagine. A business may have contracted during a difficult trading period, leaving half an office floor idle. A retailer might hand over the keys to a friend "just to cover the rent" while they try something else. In each case, the tenant sees a pragmatic solution to a cash flow problem. What they often fail to appreciate is that most commercial leases treat unauthorised subletting or sharing of occupation as a breach of covenant — sometimes a fundamental one.

What Your Lease Actually Says

Before anything else, read the lease. Three provisions matter most:

• The alienation covenant. Almost every commercial lease restricts assignment (transferring the whole lease) and underletting (granting a lease of part or all of the premises). Post-1996 leases in England and Wales are subject to the Landlord and Tenant (Covenants) Act 1995 and, for many leases, statutory lease codes that qualify absolute restrictions with reasonableness.
• The sharing or parting with possession covenant. This catches arrangements short of a formal sublease — licences to occupy, sharing premises with another business, or simply allowing someone else to trade from the unit.
• The user covenant. Even where occupation is authorised in principle, a subtenant running a different trade may breach the permitted use.

Some leases permit subletting of part with consent; others prohibit it outright. The wording will shape every option available to you.

Spotting the Signs

Landlords who visit their properties periodically rarely need forensic tools. Warning signs include:

• New signage, branding or trading names not connected to the tenant
• Different staff, opening hours or contact details on the door
• Rent paid from an unfamiliar account
• VAT invoices or business rates correspondence addressed to another entity
• A change in the nature of the business — a café becoming a barbershop overnight

If you suspect a subletting arrangement, keep records. Photographs, dated correspondence and witness observations all matter if the dispute later escalates.

Your Enforcement Options

Once you have established an unauthorised arrangement, the law offers a ladder of responses, roughly in order of escalation.

1. Correspondence and regularisation. The gentlest route is often the best first step: write to the tenant, put them on notice of the breach, and offer two outcomes — the subtenant leaves, or an application is made for consent to a formal sublease on terms the lease allows. Many matters end here.

2. Rent and costs pressure. Where the lease allows, you may be able to recover losses, increased insurance premiums or management costs caused by the breach. Keep a clear schedule of any loss.

3. Forfeiture. For serious or persistent breaches, a landlord may seek to forfeit the lease. Since the Law of Property Act 1925, this generally requires a formal section 146 notice, giving the tenant a reasonable period to remedy the breach, followed by court proceedings or peaceful re-entry in limited circumstances. Forfeiture is a powerful remedy but a technical one — mistakes can expose a landlord to claims for wrongful forfeiture, so legal advice at this stage is essential.

4. Negotiated surrender. Sometimes the cleanest answer is to bring the lease to an end by agreement, with or without compensation, and re-let the premises on fresh terms. This avoids litigation entirely and can suit both sides if the relationship has broken down.

Drafting Against It Next Time

Prevention is cheaper than cure. When granting or renewing a commercial lease, consider:

• An absolute prohibition on subletting part, or a tightly defined consent regime
• Express covenants covering sharing occupation, not just formal underleases
• A requirement that any permitted sublease be on terms no more favourable than the head lease
• Regular inspection rights, so unauthorised occupation is discovered early
• Clear provisions on authorised guarantee agreements where assignment is permitted

A Final Word

Unauthorised subletting sits at the intersection of property law, contract and pragmatism. Most tenants who breach these covenants are not bad actors — they are businesses under pressure making decisions without advice. A measured response, grounded in what the lease actually says, protects the value of your investment while leaving room for a commercial outcome that suits everyone.

If you have concerns about an occupier at one of your commercial properties, our Commercial Property team can review your lease, advise on your options and, where necessary, act quickly to protect your position.