Who has to pay the council tax ?

Usually one person, called the laible person is liable to pay the council tax. Nobody under the age of 18 can be classed as a liable person.

The hierarchy of liability is: -

1. He is a resident of the dwelling and has a freehold interest in the whole or any part of it; resident, means an individual who has attained the age of 18 years and has his sole or main residence in the dwelling
2. He is such a resident and has a leasehold interest in the whole or any part of the dwelling which is not inferior to another such interest held by another such resident;
3. He is both such a resident and a statutory or secure tenant of the whole or any part of the dwelling;
4. He is such a resident and has a contractual licence to occupy the whole or any part of the dwelling;
5. He is such a resident; a person who is resident in the dwelling includes people that may have no legal right to occupy the dwelling; for example, squatters.
6. He is the owner of the dwelling. Owner means the person who has a material interest in the whole or any part of the dwelling. "Material interest" means a freehold interest or a leasehold interest which was granted for a term of six months or more

The person liable to pay the tax is the person who's status places them highest on the hierarchy of legal interest. The person at the top of the hierarchy is the liable person. Two or more people at the same point of the hierarchy will both be liable.