In most cases landlords have to follow a special legal procedure if they want you to leave - they can't just change the locks when you are out. This is true whether you rent from the council, a housing association, or a private landlord.
It is usually illegal for your landlord to evict you without a court order. However, in some cases, you have fewer rights. Your landlord may only have to give you 'reasonable notice' to leave (which could be just a few days or less) if:
In most other cases your landlord has to get a court order (called a 'possession order') before you have to leave. Landlords normally have to give you written notice that they are going to apply to the court but if they want you to leave because of your anti-social behaviour, they can start proceedings straightaway.
The steps that landlords must follow, the amount of notice you are entitled to, and the reasons they can use to evict you depend on the type of tenancy you have. For more information, see the Community Legal Service Direct leaflet 'Renting and Letting'.
If you are facing eviction for any reason, you should get specialist help straight away. You may be able to stop the eviction, or delay it until you can sort matters out or find somewhere else to live. This is true even if the bailiffs are on the way. The rules are very complicated so you should get expert help immediately.