Supreme Court today decriminalised gay sex in a landmark judgment.

The court heard petitions challenging the constitutional validity of Section 377 of the Indian Penal Code which criminalised consensual unnatural sex.

A five-judge Constitution bench of the Supreme Court headed by Chief Justice of India unanimously decriminalised part of the 158-year-old colonial law.

The bench, which also comprised Justices R F Nariman, A M Khanwilkar, D Y Chandrachud and Indu Malhotra, struck down Section 377 as irrational, indefensible, manifestly arbitrary and violative of the right to equality.

The Supreme Court said other aspects of Section 377 remain in force. These deal with unnatural sex with animals and children remain.

The United Nations lauded the supreme court and said the judgment will boost efforts to eliminate stigma and discrimination against LGBTI persons.

It also hoped the ruling will be the first step towards guaranteeing the full range of fundamental rights to LGBTI persons.