Part 3 of Children and Families Act 2014
https://www.legislation.gov.uk/ukpga/2014/6/part/3/enacted

The Special Educational Needs and Disability Regulations 2014
https://www.legislation.gov.uk/uksi/2014/1530/contents/made

SEND code of practice: 0 to 25 years
https://www.gov.uk/government/publications/send-code-of-practice-0-to-25