Pope Benedict XVI has ushered in Christmas at the Vatican as he led the celebration of Midnight Mass in St Peter’s Basilica.The service was sold out weeks ago, meaning crowds of worshippers and tourists braved the cold in Rome to stand outside and watch the service on giant screens. People in 400 countries around the World watched the event on television. The Pontiff used the occasion to call for peace in the Middle East. He is due to visit the region next May. Thousands of Christian pilgrims gathered in the West Bank town of Bethlehem, under the protection of security forces loyal to Palestinian President Mahmoud Abbas. A comparative lull in violence has persuaded many worshippers to make the trip to Manger Square.