Children have been disproportionately affected by the COVID-19 pandemic. Despite evidence of a very low risk of severe disease, children were subjected to extensive lockdown, restriction and mitigation measures, including school closures, to control the rapid spread of SARS-CoV-2 in most parts of the world. In this review we summarise the UK experience of COVID-19 in children four years into the largest and longest pandemic of this century. We address the risks of SARS-CoV-2 infection, immunity, transmission, severity and outcomes in children. We also assess the implementation, uptake, effectiveness and impact of COVID-19 vaccination, as well as the emergence, evolution and near disappearance of PIMS-TS (paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2) and current understanding of long COVID in children. This review consolidates current knowledge on childhood COVID-19 and emphasises the importance of continued research and the need for research-driven public health actions and policy decisions, especially in the context of new variants and future vaccines.