In a surprise move which will dismay some traditionalists the Vatican has this year done away with the Christmas manger scene on St Peters Square, replacing it with a scene showing Joseph's house and carpenter's shop in Nazareth.

The giant Christmas tree on the square was today illuminated. The Nativity scene next to it is still being constructed behind fencing hiding it from view and will not be unveiled until Christmas Eve.

However Vatican officials said it showed not the traditional stable with an ox, an ass and the Three Wise Men but the scene in Nazareth before the birth of Jesus, when Joseph was told in a dream that Mary was to bear the son of God.

The traditional stable scene is taken from the Gospel of St Luke, which describes how shepherds were told by angels to go to Bethlehem, where "they came with haste and found Mary and Joseph and the babe lying in a manger". It is also Luke who says that Mary and Joseph laid Jesus in a manger "because there was no room for them in the inn".

Vatican officials said the change of Nativity scene was not intended to detract from the traditional crib tableau, but was because the Holy See had this year chosen the Gospel of St Matthew as its Christmas text. Matthew also says that Jesus was "born in Bethlehem in Judea in the days of Herod the King". But the focus in his narrative is on Nazareth, describing how "when Mary was espoused to Joseph, before they came together, she was found with child of the Holy Ghost".

He then tells how "Joseph, being a just man, and not willing to make her a public example", wanted to hide her away, until an angel appeared to him assuring him that "that which is conceived in her is of the Holy Ghost". When Joseph awoke from his dream "he did as the Angel of the Lord had bidden him and took unto him his wife, and knew her not untl she had brought forth her first born son, and he called his name Jesus".

The St Peters Square Nativity scene has shown a variation of the manger story for a quarter of a century.The new tableau shows the baby Jesus in Joseph's house at Nazareth -as in his dream - and Josephs workshop with "the typical work tools of a carpenter". It also reportedly depicts the Holy Family's later Flight to Egypt after Herod's massacre of the innocents.