Trafalgar Square's Christmas tree has been lit up, marking a 57-year tradition.
The tree is about 75 ft tall
The spruce is an annual gift from the people of Norway as a token of gratitude for Britain's support during World War II.
This year the 75-feet-high tree will stand in a newly-refurbished square.
London mayor Ken Livingstone was joined at the lighting ceremony, by the Norwegian ambassador and the Mayor of Oslo.
The tree will remain in the square, illuminated from noon to midnight, until 6 January 2004 - the traditional Twelfth Night of Christmas.
The choir of St Martin-in-the-Fields church performed carols at the lighting ceremony, which will also be attended by the Lord Mayor of Westminster.
And from Saturday, 6 December up to Christmas Eve, the square will host free carol concerts, with donations going to different charities.
"The carol concerts and the Norwegian Christmas tree will bring some truly festive spirit to the square for Londoners as well as visitors," said Mr Livingstone.