Procedure Goes Like This:
Your arrested on a sexual offence charge which you dispute. It was either consensual or never happened or is historical.
You are interviewed by the police. All the police have is an allegation (a claim or assertion that someone has done something illegal or wrong, typically one made without proof). The police are instructed to believe the complainant, therefore everything you say is a lie. What they want from you is confirmation that you committed the offence. You have nothing to hide, and start talking. Talking your way into prison.
The police place before you some vague times when they claim the offence occurred. You state the offence couldn’t happened for various reasons. You say for example you were out the country at that time. The police and Crown Prosecution Service will re-interview the complainant and the dates will be change.