Sophie Dahl and Sandi Toksvig switch on Christmas lights

The Hayward invited contemporary artist Anya Gallaccio to create this year's Festive Lights commission at the Southbank Centre.

Anya Gallacio has adorned a section of the Royal Festival Hall's western wall with just under 1,000 individually hand-tinted light bulbs, each a varying shade of green. The bulbs turn off and on according to programmed rhythms that use Morse code to transmit the lyrics of three popular Christmas songs – Frosty the Snowman, Jingle Bells and White Christmas.

A second installation, composed of hundreds of hand painted red bulbs, illuminates the front eastern corner of the building.

David Batchelor's 2006 commission, Festival Remix, has returned to the Southbank Centre. Inspired by refurbishment work at the Royal Festival Hall, Batchelor transformed mundane building tools such as bins, pallets and cement mixers into glowing forms. These illuminated objects are complemented by festoons of lights, each in its own recycled plastic bottle.

Meanwhile at Emma Cons Gardens Sandi Toksvig switched on Waterloo's Christmas lights at a ceremony organised by Waterloo Quarter Business Alliance. Toksvig is the narrator of Stephen Fry's new version of Cinderella which opens this week at The Old Vic.

• On Friday night Lucinda Dickens Hawksley, great-great-great granddaughter of Charles Dickens, switched on the Christmas lights at Red Cross Garden in Redcross Way.