“I henceforth grant to all priests … the faculty to absolve those who have committed the sin of procured abortion. The provision I had made in this regard, limited to the duration of the Extraordinary Holy Year, is hereby extended,” he said in an Apostolic Letter.

The pope added: “I wish to restate as firmly as I can that abortion is a grave sin, since it puts an end to an innocent life. In the same way, however, I can and must state that there is no sin that God’s mercy cannot reach and wipe away when it finds a repentant heart.”

The decision is another example of Francis’ readiness to apply flexibility when it comes to rules. He has often said that he prefers mercy to doctrinarian rigidity, a stance that has put him at loggerheads with conservatives.

The Catholic Church has condemned abortion as a “moral evil” since its earliest days. In Canon Law, it is deemed worthy of automatic excommunication, applicable also to partners who support abortion decisions and medical staff involved in the procedure.

Catholics for Choice, a US group that supports abortion rights, praised the pope for taking “a much more pastoral, rather than political, approach to abortion — one of the most contentious issues in the Catholic Church.”

Archbishop Rino Fisichella, a top Vatican official who organised the holy year festival, said the event drew almost 21.3 million pilgrims to Rome.

The top five countries of origin for pilgrims were Italy, Germany, the United States, Poland and Spain, he added.

Jubilees offer the faithful a chance to seek a general pardon for their sins as they walk through symbolic holy doors. The main one is in St Peter’s Basilica, but Francis decided to place them across the globe, so that pilgrims would not necessarily have to travel to Rome.

Factoring in this innovation, “more than 900-950 million faithful around the world” have taken part in the festival, Fisichella said at a news conference, implying a participation rate of more than 70 per cent among the global Catholic population of 1.27 billion.