This depends on what offence you are charged with and what it is you are hoping to achieve with the letter. for example, if you are charged with drink driving then it really doesnt matter what the letter says, if you are convicted and there are no special reasons you are going to get banned for at least 12 months.
You need to take specific advice tailored to the circumstances of your case from a solicitor. If you want help with this then call our helpline and speak to one of our lawyers who specialise in this area on 08450020736