Advanced: G*0xxx, G*1xxx, G*2xx, G*2xxx, G*3xx, G*3xxx, G*4xx, G*4xxx,
            G*5xx, G*6xx, G*6xxx, G*7xxx, G*8xx, G*8xxx, M*0xxx, M*1xxx, M*5xxx
Intermediate: 2*0xxx, 2*1xxx
Foundation: M*3xxx, M*6xxx, M*7xxx
Repeater: GB3xx, GB7xx (data repeater)
Beacon: GB3xxx
Data Mailbox: GB7xxx

 xx = 2 letters (e.g. ZZ, HK, PY etc)
xxx = 3 letters (e.g. JPZ, UFG, SDI etc)

*= Regional designator:
no letter = England (Advanced and Foundation Licenses only)
B = Special Event Station anywhere in the UK
C = Wales, club station
D = Isle of Man
E = England (Intermediate Licences only i.e. 2E0XXX or 2E1XXX but not ME...XXX or GE...XXX)
G = Special Event Station designator last used to celebrate Girl Guiding
H = Jersey, club station
I = Northern Ireland
J = Jersey
M = Scotland
N = Northern Ireland, club station
O = Special designator last used to celebrate the 2012 London Olympic Games
P = Guernsey club station
Q = Special designator last used to commemorate the Queen's Diamond Jubilee
R = Special designator last used to celebrate the marriage of Prince William and Miss Catherine Middleton
S = Scotland, club station
T = Isle of Man, club station
U = Guernsey
V = Proposed special designator to celebrate 100 years of the RSGB in 2013
W = Wales
X = England, club station

Permitted suffixes are:

/M = Mobile
/MM = Maritime Mobile
/P = Portable
/A = Alternative fixed address

The suffix /QRP is not permitted.