Hundreds of same-sex marriages have been annulled in Italy after the Council of State removed their legal status.

On Tuesday a ruling in favour of cities that had registered same-sex marriages was annulled by the country's highest appeal court.

Same-sex marriage is not legal in Italy, which is un-surprising in a country heavily influenced by the Vatican. Despite this, some liberal mayors have been defying the law by registering unions that have occurred abroad.

The decision of the Council of State has been met with outrage from gay rights groups, particularly when it was found that the panel of judges was led by a former president of an Opus Dei-run halls of residence in Milan.

Opus Dei is a secretive, conservative Catholic society whose members are known to live strictly pious lifestyles.

Another of the judges was accused of allowing his conservative Catholic beliefs, declared publicly on his Twitter profile, which he denied and insisted he "merely applied the law."

Foreign ministry undersecretary and member of the centre Left PD party, Benedetto Della Vedova, said the ruling was "a victory for no one and a defeat for all", as it leaves Italy "at the starting posts as regards gay rights, which urgently need to be regulated."

A bill introducing civil unions for same-sex couples is being examined by parliament but has been met by strong opposition.

Significantly, the recognition of same-sex marriages would give gay couples the same financial benefits and security as heterosexual married couples.