Is it mandatory to be at least 21 years old to serve on a jury?

The minimum age to serve on a jury in the UK is actually 18, the same age you gain full adult rights and responsibilities. The idea behind jury service is that it should represent a cross-section of society, and that includes young adults. Think about it: young people are affected by laws and legal decisions just as much as older people, so it makes sense for them to have a voice in the justice system. The rules about jury service are governed by the Criminal Justice Act of 2003. While there are certain disqualifications, like having a serious criminal record or a mental disorder, being under 21 isn't one of them. It's easy to assume a higher age, perhaps because jury duty is a serious civic responsibility, but the UK trusts its 18-year-olds to participate fully.