Forfeiture: the waiver trap most tenants — and landlords — walk into

Two very different routes, depending on the breach

If a commercial tenant is behind on rent, a landlord doesn't need to serve any notice before re-entering — that route is available immediately. Any other breach — unauthorised subletting, a change of use, a repair covenant broken — needs a Section 146 notice served first, under the Law of Property Act 1925. The notice has to spell out the breach, give the tenant a reasonable chance to fix it if it's fixable, and set out any compensation sought. Skip that step, or get it wrong, and the whole forfeiture is open to challenge.

Waiver: the trap that catches people who did everything else right

Here's the part that trips landlords up constantly, and it has nothing to do with the notice itself. If you accept rent after you know about a breach — even if it's your accounts team doing it automatically, without knowing there's a problem — you can lose the right to forfeit entirely. This isn't a technicality dreamed up by lawyers to be difficult. Courts have held that even an automated rent demand sent by an employee who didn't know about the breach counts as waiver.

The distinction that matters here: a "once-and-for-all" breach — an unauthorised assignment, an illegal sublet — is waived permanently the moment you accept rent knowing about it. Gone, full stop. A "continuing" breach — an ongoing disrepair issue, a prohibited use that's still happening — is different: accepting rent only waives it up to that point, and a fresh right to forfeit arises immediately for the breach continuing after.

What that means in practice, before you do anything else

The moment you're aware of a breach and thinking about forfeiture, stop every automated rent demand immediately, tell your accounts and managing agents not to touch it, and return anything tendered rather than banking it. Any of these done without thinking can hand the tenant a defence that has nothing to do with whether the breach actually happened.

Peaceable re-entry has its own rules too

Even once you're clear to act, re-entry has to be genuinely peaceable — no force, no threats, and it can't happen while the premises are occupied. Get that wrong and you're exposed to a wrongful forfeiture claim, on top of everything else.

The tenant's side of this

If you're the tenant facing this, you're not automatically out of options. Relief from forfeiture is available within six months of peaceable re-entry — the court can restore the lease, sometimes on terms, if you act within that window.