Section 7 of the Education Act 1996 applies to England and Wales:
7 Duty of parents to secure education of children of compulsory school age
The parent of every child of compulsory school age shall cause him to receive efficient full-time education suitable—
to his age, ability and aptitude, and
to any special educational needs he may have,
either by regular attendance at school or otherwise.
Home education is covered under “education otherwise” and ensures that every parent has the right to chose not to send their child into the state schooling system.
Education Otherwise have a summary of the law which can be downloaded on their website here.
The rights of a parent to chose their childs education is also further enshrined in the Universal Declaration of Human Rights which says “Parents have a prior right to choose the kind of education that shall be given to their children” (Article 26, para 3).