According to the Health Survey for England, in 2015 22% of children (23% of boys and 20% of girls) aged 5-15 met the physical activity guidelines of being at least moderately active for at least 60 minutes every day. This is higher than in 2012, when 21% of boys and 16% of girls met the guidelines. However this excludes school-based activities and active travel. Further information can be found here: https://www.gov.uk/government/publications/uk-physical-activity-guidelines.
As part of the government’s Sporting Future strategy, Sport England’s remit was extended to cover children from age 5+. Government departments including DCMS, DfE and DHSC have worked with Sport England to develop the new Active Lives: Children and Young People survey. This survey launched in schools in September 2017 and will measure in much more detail how children and young people engage in sport and physical activity, and how many are meeting the Chief Medical Officer's guidelines, both in and out of school. The first set of data will be available on 6 December.