Just to provide a bit of background to Sumo19's (excellent) answer:
The investigation into the Soham murders strongly criticised the police for failing to mention, on Ian Huntley's enhanced CRB check, that he had been questioned on several occasions relating to unproved allegations of sexual misconduct. Since then all police forces have always 'erred on the side of caution' and included any relevant information that they hold on enhanced CRB checks.
For example, a teacher posted here on AB saying that his CRB check had shown that he'd been accused of 'grooming' a child for sex, even though he'd never been questioned about any such allegation (or even been told that it existed). I also know of a teacher who found that her husband's conviction for a sexual offence was included on her CRB check.
If your employment means that you'll have to undergo an enhanced CRB check, even the slightest suspicions raised against you or anyone you live with (even if completely untrue) are likely to be reported.
Chris