you will probably be on a fixed term short tenancy agreement, so it will automatically run out unless you renew. the notice to terminate the contract will already be in the contract normally, but the purpose of the short tenancy agreement is to protect you as the tenant and i believe that you still need to be served notice.

this is just my experience from renting houses for 10 years, and is not necessarily the law. contact your local citizens advice bureau for proper advice - that is what they are there for