The police MUST issue what is known as a Notice of Intended Prosecution (NIP) if they intend to prosecute a motoring offence which was NOT involved in an accident. S1 Road Traffic Offenders Act 1988 requires police to:
If the notices are not served in time or they are not correctly served you may avoid a conviction. Note that you DO NOT COUNT the day of the alleged offence, so if the alleged offence is committed on the 1st of the month the notice should be served by the 15th of the same month.