Ali G's festive cheer

Christmas in Staines: Ali G is Channel 4's Christmas star

Cult comedy creation Ali G will compete with the Queen when he gives Channel 4's alternative message on Christmas Day.

The spoof hip-hop fan, created by Sacha Baron Cohen, has bewildered politicians and other public figures on The 11 O'Clock Show.

He follows in the footsteps of Neville and Doreen Lawrence, Brigitte Bardot, and the late Quentin Crisp.

Meanwhile, the channel could face controversy over its screening of the modern opera Powder Her Face. Written by the acclaimed composer Thomas Ades, it features an oral sex scene shortly after the 2100 watershed.

Graham Norton gets in the festive spirit

The opera is based on the "headless man" incident involving Margaret, Duchess of Argyll, in which she was pictured in a sex act with a mystery man. The photographs emerged in her 1963 divorce case and caused a sensation.

Ades, 28, was nominated for the Mercury Music Prize earlier this year for his album Asyla. It won the world's largest composer's prize, the £160,000 Grawemeyer award, earlier this week.

A Channel 4 spokesman said the scenes were not explicit and the opera had already been performed widely.

"It's part of the Channel 4 tradition of providing an alternative at Christmas," he added.

Millennium night programming will be led by a Graham Norton special, FY2K. The camp comedian will broadcast live from the South Bank in London, as he follows the Queen's progress up the River Thames to the Millennium Dome.

Jon Snow will leave the studio to travel the prime meridian

Shortly after midnight Johnny Vaughan and Liza Tarbuck will take over for The Biggest Breakfast Ever, which will last for eight hours.

Festive drama includes a hour-hour adaptation of Dava Sobel's novel Longitude - a tale of intrigue and power in 18th century England - starring Michael Gambon and Jeremy Irons.

Kathleen Turner will lead the cast of a contemporary version of Cinderella on New Year's Day, while free-to-air film premieres include Welcome To Sarajevo and Carla's Song.

On The Line is a season of programmes looking at life in other countries which share Greenwich Mean Time with the UK. It sees Channel 4 News presenter Jon Snow following the prime meridian to Timbuktu in Living On The Line.

Slade frontman Noddy Holder - whose Merry Xmas Everybody is an enduring seasonal record - looks at other festive hits in Christmas Top Ten, while there will be special editions of Eurotrash, Something For The Weekend and Time Team.