The license gives access to all Amateur Radio frequencies above 30 megahertz, allowing these licensees the ability to communicate locally and most often within North America.It also allows for some limited privileges on the HF (also called "short wave") bands used for international communications.
If you fail to revalidate, Ofcom may revoke your licence.
Earning the General class license requires passing a 35 question examination.
General class licensees must also have passed the Technician written examination.
Extra class licensees must also have passed all previous license class written examinations.
Edit: This applies only to FCC-issued call signs, such as US call signs.
Note that this can occur where you have failed to inform Ofcom of a change of contact information (thus preventing their reminders/notifications reaching you). However postal and other applications (including reinstating a lapsed licence) may incur a fee.