They must serve a notice on the tenant, establishing what act(s) of the tenant are in breach of the lease, giving them 2 months’ notice before their eviction. The notice also needs to be submitted to the First-tier Tribunal, to put them on notice that the landlord is seeking to exercise their right to forfeit, under section 168 Commonhold and Leasehold Reform Act 2002

Given the severity of the consequences of forfeiture for the tenant, section 146 Law of Property Act 1925 requires that an initial notice served in writing must be followed with another notice served between 14 and 28 days later if it is to be enforceable

A landlord need not serve notice on a tenant whose breach is objectively incapable of being remedied because it involves criminality or illegality that leaves an enduring stigma

They must serve a notice on the tenant, identifying the specific covenant that has been breached, offering the leaseholder an opportunity to remedy the breach, and demand payment of additional compensation for the breach