Which of the following best describes summary offences?

Summary offences are indeed best described as the least serious offences tried in Magistrates' Courts. This classification is important in the context of the criminal justice system, as summary offences typically include minor infractions such as minor theft, public order offences, or driving offences. Because of their relatively low severity, these cases are handled quickly and do not require the involvement of a jury. Instead, they are decided by a magistrate or a panel of magistrates, which streamlines the legal process for these less serious crimes.

The context around this categorization distinguishes summary offences from indictable offences, which are more serious and heard in Crown Courts with a jury present, along with either-way offences that can be tried in either court depending on the specifics of the case. Additionally, while some summary offences may carry a fixed penalty, not all must adhere to this structure, making the distinction with having only fixed penalties less precise as a defining feature. Therefore, identifying summary offences as the least serious, involving no jury and heard in Magistrates' Courts, accurately encapsulates their legal standing.