http://en.wikipedia.org/wiki/Council_Tax#Exemptions
A Vacant dwellings where major repair works or structural alterations are required, underway or recently complete (up to twelve months).
B Unoccupied (and furnished) dwellings owned by a charity (up to six months).
C A vacant dwelling (i.e. empty and substantially unfurnished) (up to six months).
D A dwelling left unoccupied by people who are detained in prison. Normal rates apply if they are imprisoned for non-payment of Council Tax.
E An unoccupied dwelling which was previously the sole or main residence of a person who has moved into a hospital or care home.
F Dwellings left unoccupied by deceased persons.
G An unoccupied dwelling where the occupation is prohibited by law, however squatters can still be charged normal rates if they are found to be residing there.
H Unoccupied dwellings of ministers of any religion.
I An unoccupied dwelling which was previously the sole or main residence of a person who is the owner or tenant and has moved to receive personal care.
J An unoccupied dwelling which was previously the sole or main residence of a person who is the owner or tenant and has moved to provide personal care to another person.
K An unoccupied dwelling where the owner is a student who last lived in the dwelling as their main home.
L An unoccupied dwelling that has been taken into possession by a mortgage lender.
M A hall of residence provided predominantly for the accommodation of students.
N A dwelling which is occupied only by students, the foreign spouses of students, or school and college leavers.
O Armed forces' accommodation.
P A dwelling where at least one person who would otherwise be liable has a relevant association with a visiting force.
Q An unoccupied dwelling where the person who would otherwise be liable is unable to make use of the property because it is with a trustee in bankruptcy.
R Empty caravan pitches or boat moorings not in use.
S A dwelling where all occupants are aged under 18.
T A dwelling which forms part of a single property which includes another dwelling and may not be let separately from that dwelling, without a breach of planning control.
U A dwelling occupied only by a person, or persons, who is or are severely mentally impaired who would otherwise be liable to pay council tax or only by a one or more severely mentally impaired persons and one or more students, students' foreign spouses and school and college leavers.
V A dwelling in which at least one person who would otherwise be liable is a diplomat.
W A dwelling which forms part of a single property including at least one other dwelling and which is the sole or main residence of a dependant relative of a person who is resident in the other dwelling.