If you use a section 21 message, you are essentially informing your tenant that you will not renew the rental agreement at the end of the duration of the limited period and that he will therefore have to leave the indicated termination date (provided that the termination is properly served). In this case, an owner does not need a reason to repossess his property and no one can challenge the owner`s right. As I said, clean as a whistle. In practice, 12-month leases are the norm, as they offer a good balance between ensuring sufficient rent for the lessor and sufficient freedom for the tenant to leave the lease after a reasonable period of time. The problem with oral leases is that they can be difficult to enforce. In the event of a dispute, a court should hear evidence and decide who will accept the version of the truth.