Pop Idol winner Will Young has failed to make it four number one singles in a row as Christina Aguilera holds on to the top spot.

But Robbie Williams can celebrate yet another chart-topper as his latest album Escapology enters at number one, knocking Westlife's Greatest Hits off the top.

Young's Double A-side Don't Let Me Down/You and I was the official Children in Need charity single and entered the chart at number two.

He has previously scored number ones with Evergreen, Light My Fire and The Long and Winding Road, a duet with Pop Idol runner-up Gareth Gates.

Aguilera stayed at number one for a second week with her single Dirrty - spelt with a double r - fending off competition from Young and Jennifer Lopez, whose single Jenny from the Block entered at number three.

Shania Twain crosses country and pop boundaries

Rapper Nelly and Destiny's Child's Kelly Rowland's former number one Dilemma slipped to number four.

Making up the top five is a new entry from S Club with Alive.

Mariah Carey's first single since signing to a new record label, Through the Rain, entered at number eight.

Robbie Williams' popularity continues as his latest pop album reached the top.

Country star

The previous album Swing When You're Winning, a collection of big band tunes, was the big seller of Christmas 2001.

The album charts is a mixture of veteran artists and young pretenders as teenager Avril Lavigne rubs shoulders with Elvis Presley and Jools Holland.

There has been a massive leap in sales of Rod Stewart's latest album It Had to be You, which climbed from number 107 to number eight after he completed a hectic round of television chat show appearances.

Elton John's Greatest Hits album has fallen from number three to five.

Canadian country singer Shania Twain achieved the second highest new entry at number four with Up.