The Department and MHCLG explained that there were different calculations for SEND and mainstream funding to account for the additional costs associated with SEND transport, but that both were based on pupil populations and adjusted distances to school. For both mainstream and SEND transport, the formula uses pupil populations for children of compulsory school age only (5–16 years); it does not cover funding for post- 16 transport.57 Although at £0.2 billion in 2023–24 it represents a small proportion of overall spending, the Department told us SEND-related transport for 16 to18-year-olds was growing even faster than for those aged 5 to 16.58