If you agree to take up accommodation, the landlord/lady or agency and you should sign an agreement which will be either a tenancy or licence, depending on the type of accommodation you are renting.
Your rights as an occupier will depend on the type of agreement that you have, so it's worth checking that you have the right sort of agreement. You will probably either have an Assured Shorthold Tenancy or a Licence to Occupy.
It is important to bear in mind the following:
If in doubt get advice - and don't sign until you are completely happy.
The rights and responsibilities that you have as an occupier will also be affected by whether you have a joint tenancy or an individual agreement.
If you sign one agreement for a property as a group you will have a joint tenancy. This means that you are all jointly responsible for the rent and all other terms in the tenancy agreement. If one person leaves the property before the end of the contract, all the joint tenants still in the property could be held liable for paying the whole of the rent.
The fairest solution is usually to find a replacement tenant that everybody agrees to. If you do this, make sure that the person who takes over your room takes over all your legal responsibilities as a tenant, as sometimes a landlord/lady will add a clause to the agreement or ask that you are responsible for the rent if the new tenant doesn't pay. The safest thing to do is to get a new tenancy agreement signed in the names of the new group of people. If possible get separate tenancy agreements drawn up rather than joint ones.
Remember, once you have signed a contract you are bound by the terms and conditions of that contract.