You accepted the caution - did they tell you this was an admission of guilt?
If you didn't do any of the things you were accused of you should not have accepted the caution and let them pursue it through the courts, if it had got that far.
A simple caution is not a criminal conviction, but it will be recorded on the police database. It may be used in court as evidence of bad character, or as part of an anti-social behaviour order (ASBO) application.
The record will remain on the police database along with photographs, fingerprints and any other evidence taken. If you are cautioned for a sexual offence, you could be placed on the sex offenders register.
If a crime victim requests your name and address for civil proceedings, the police are legally obliged to give this information out, so you may still be sued for damages. "
http://www.homeoffice.gov.uk/police/powers/cau tioning/