The Trafalgar Square Christmas tree lights were turned on in a special ceremony on Thursday evening.
Mayor of London Sadiq Khan was joined by the Mayor of Oslo, Anne Lindboe, to mark the traditional event in central London.
This year’s tree is a 19-metre-tall Norwegian spruce from the Nordmarka Forest and was given to the capital by Norway as a token of gratitude for British support during the Second World War in a tradition that stretches back to 1947.
The tree was hailed as "the best in years" after undergoing a branch transplant to improve its appearance.
The 70ft fir tree initially came in for criticism on social media as it arrived on Monday morning, but Westminster City Council confirmed branches were removed from the tree in Norway for transportation before being reattached.
The event was also marked by the publication of a poem T is for Tree byeco-poet Isabel Galleymore.
The verse, commissioned by the Poetry Society and inspired by the tree's journey from the Norwegian forest to the capital, was read on the night by a trio of local schoolchildren from Westminster's St Mary of the Angels Catholic Primary School.
It was also displayed on a lightbox near the base of the tree where it is expected to be seen by millions of passersby until the tree comes down on January 6.
Poetry Society Director Judith Palmer said: "‘The society commissions a poem every year in gratitude for the arrival of this special tree from Norway.
"It’s become a bit of a tradition recently to body-shame the tree because it doesn’t fit people’s Disneyfied idea of a perfect tree.
"We wanted this year’s poem to celebrate the unique character of the Trafalgar Square tree, recognising its magic as a genuine forest tree that has lived out under the sky through all seasons, sheltering birds and insects in its branches, and naturally decorated with beautiful lichen."
