What you should know
Penalties;
The minimum penalty for speeding in the UK is a £100 FINE and 3 penalty points endorsed on your driving licence. Endorsements stay on your licence for at least 4 years after that date of the conviction. Your licence will be revoked if you accumulate more than 12 penalty points.
If you have passed your driving test within two years, you will have your driving licence revoked if more than 6 points have been accumulated.
Defences;
If you accept that you were above the speed limit, you can either accept the allegation in full or alternatively, you can argue the exact speed alleged. Both options will result in a guilty plea, the latter is known as a Newton Hearing, allows you to dispute the exact speed with a view to obtaining a reduced punishment.
Alternatively, you can contest the speed itself or deny the allegation in its entirety. If you choose to do this court proceedings will commence and you will have to attend at a full hearing.