Special educational needs and disabilities (Send) is the "biggest issue" affecting schools in England, Ofsted's chief inspector has said.
Sir Martyn Oliver told the education committee that the Send system's high costs and poor outcomes represented a "lose-lose situation".
Government figures for the 2023/24 academic year showed more than 1.6 million children had Send, an increase of 101,000 from 2023.
Sir Martyn said the inspectorate had a duty to support the government in its plans to provide for Send children.