Everybody has the right to an effective education.
Parents also have a right to ensure that their religious and philosophical beliefs are respected during the children's education.
The right to education does not give you the right to learn whatever you want, wherever you want.
The courts have ruled that the right to education relates to the education system that already exists. It does not require the government to provide or subsidise any specific type of education. This does not oblige the state to fund religious schools of any kind.
The government is allowed to regulate the way education is delivered. For example, it can pass laws making education compulsory or imposing health and safety requirements on schools.
School admission policies are permissible so long as they are objective and reasonable.
Although parents have a right to ensure their religious or philosophical beliefs are respected during their children's education, this is not an absolute right. So long as these beliefs are properly considered, an education authority can depart from them but only if there are good reasons for doing so and it is done in an objective, critical and pluralistic way.
What the law says
Protocol 1, Article 2: Right to education
No person shall be denied a right to an education. In the exercise of any functions which it assumes in relation to education and to teaching, the State shall respect the right of parents to ensure such education and teaching in conformity with their own religious and philosophical convictions.
From the Foreign and Commonwealth Office Freedom of Religion or Belief Toolkit:
Human rights treaties give parents and legal guardians the right to educate their children in accordance with their religion and philosophical convictions, and children should not suffer discrimination because of this. The state is not obliged to actively participate or provide resources to assist parents in such religious education; parents do not have a right to state funding for confessional religious teaching or religious schools that are in line with their own beliefs.
The Convention on the Rights of the Child recognises childhood as ending at 18, noting that the child's views should progressively be taken into account as s/he develops capacity."