Cardinal Robert Sarah, the Vatican’s liturgy chief, has asked priests to begin celebrating Mass ad orientem, that is, facing east rather than towards the congregation.

The proposed reform is arguably the biggest liturgical announcement since Benedict XVI’s 2007 motu proprio Summorum Pontificum gave greater freedom for priests to celebrate the Traditional Latin Mass.

Speaking at the Sacra Liturgia conference in London on Tuesday, the Guinean cardinal, who is Prefect of the Congregation for Divine Worship, addressed priests who were present, saying: “It is very important that we return as soon as possible to a common orientation, of priests and the faithful turned together in the same direction - eastwards or at least towards the apse - to the Lord who comes”.