RYA Junior Learn to Sail

The Youth Scheme is usually completed in small dinghies suitable for your size. However, it can also be completed in keelboats and multihulls. To make the most of our courses, ensure you are confident with the skills of one course before moving on to the next course. Most courses are a minimum of two days long (or an equivalent number of short sessions). They may be run over a longer period, especially if you haven't sailed since your last course. Sailing is a sport which gets better with practice, and you should try to sail between courses whenever you can. Practice makes perfect
https://www.rya.org.uk/training/courses/youth-sailing-scheme-start-sailing-stage-1-sss1c

Minimum age 7, Maximum Age 15.