If you know that you were speeding and are intending to plead guilty, it may be worthwhile to try to plea for a lower sentence due to mitigating circumstances. This is particularly true if you were considerably over the speed limit and are being dealt with by way of summons.
Mitigation may include the circumstances involved at the time of the speeding offence, eg a serious emegency, or the hardship that would be caused to others especially for instance family members if you were to lose your licence.
Mitigating circumstances could include:
A reason why you were speeding (especially medical emergency)
Hardship you would face by losing your licence - loss of job, family transport particularly if their is illness or other special needs in the family
Family circumstances
It can often be worth attending court in person if you wish to make a mitigating plea. Here are some useful hints