Valid grounds can include rent arrears or a serious breach of the tenancy, as well as the landlord genuinely intending to sell, move into the property, carry out substantial refurbishment, change its use, or because it is no longer suitable for the household. The rules can depend on when the tenancy began and whether it is a fixed-term tenancy. The landlord must serve a correctly drafted Notice of Termination, give the required notice period and, where relevant, provide supporting evidence and follow the RTB process. A landlord cannot lawfully evict you by changing the locks or using force; the RTB ultimately decides disputes based on the individual facts.