Assuming you have received a Notice of Intended Prosecution, if you wish to challenge the ticket then you should decline the offer of a fixed penalty (if one has been offered) and plead not guilty, which will then result in you attending court. However, we would ensure that you had strong evidence to refute the police's claim and seek independent legal advice, as if found guilty you will likely receive a higher fine than if you had plead guilty at the first stage. You can read more about the process in our guide here - www.honestjohn.co.uk/advice/driving-advice/speedin.../