Although accepted as the normal protocol across the United Kingdom, children starting school at 5 years old is actually quite unusual. The most common age to start school across the world is at age 6. So why the differences and what are the effects? With most issues in childcare and education the answer is a bit more complicated than a yes or no. It very much depends on what school and what children. Here we explore these issues in more detail to help parents understand this widely discussed question.