I'll try to be a little more helpful than pink-kittens!
Offences which are dealt with by way of a Conditional Discharge (CD) become officially “spent” when the period of the discharge is over. This means that you do not need to mention the offence when, say, applying for a job (unless it is a job which is exempt from the provisions of the Rehabilitation of Offenders Act).
Similarly, you cannot now be dealt with in a different way for that original offence. (If you commit an offence within the period of a CD the court can punish you for the new offence and for the offence which attracted the CD).
However, your conviction may be raised (or “cited”) in court if and when you are convicted of the new offence. Whether it is would be up to the magistrates (or judge if it is a Crown Court mater). If the old offence is similar in nature to the new offence and it was committed within about five years, it is likely to be cited.
The purpose of citing your previous record is so that earlier offences can be taken into consideration when sentencing.