When a youngster travels alone, the parent or legal guardian must pay the adult fare. In addition to the cost of the journey, British Airways Unaccompanied Minor Fee of around $50 is charged by the airlines for short-haul and UK-domestic flights and $75 for international flights. Along with booking and paying for the child's flight, the parent or legal guardian is also required to reserve and pay for the Skyflyer Solo service. British Airways will impose cancellation and reissue fees if this is not done. Additionally, Skyflyer Solo service must be reserved at least 48 hours before the scheduled departure time.
https://airlinespolicy.com/una....ccompanied-minors/br