writ of habeas corpus in child custody matters – The writ of habeas corpus is an extraordinary remedy used to secure the liberty of the subject – Writ of habeas corpus is maintainable when it is proved that the detention of a minor child by a parent or others was illegal and without any authority of law – The power of the High Court in granting the writ is qualified only in cases where the detention of a minor by a person who is not entitled to his legal custody –