Barry Geraghty rode Kicking King to Gold Cup glory in 2005

The 10-year-old has been in mediocre form since returning from a tendon problem and a poor training run resulted in him being withdrawn.

"His legs are fine but the quality wouldn't be up to Gold Cup standard," said owner Conor Clarkson.

Meanwhile, jockey Graham Lee will also miss the Festival because of injury.

Lee fractured his jaw in two places when he was kicked after a fall at Huntingdon in early February.

"He's fine really but he won't be back for Cheltenham," said Lee's agent Richard Hale. "He won't be allowed to ride there and that's just the way it is.

"He's consulted with Dr Michael Turner (the British Horseracing Authority's medical adviser) and is hoping to be back for Easter Saturday.

Lee suffered a broken jaw and some concussion in a fall

"That's the earliest he's likely to be back but no firm dates have been set as yet."

Lee took the Daily Telegraph trophy as the Festival's most successful jockey in 2005, the same year as Kicking King's Gold Cup triumph.

But there will be no repeat of that for trainer Tom Taaffe's horse this year.

"Obviously there's just something a little bit amiss at the moment," added Clarkson.

"He's just not firing on all cylinders. We've therefore no option but to say he will not be running in the Gold Cup."

But the horse's connections were keen to stress that they had no thoughts of retiring Kicking King, with their attentions turning to the Punchestown Gold Cup in April.

"This has nothing to do with his retirement, it is just the quality of his work," insisted Clarkson.

606: DEBATE What does this news mean for the Gold Cup?

"His work was reasonable but Tom is an astute trainer and Barry Geraghty is a top jockey.

"The quality of his work was just not up to the quality that he'd been producing in the last couple of months.

"There may be a lingering, low-grade virus there and he'll have a nice little break now.

"The Punchestown Gold Cup is now the target."

Kicking King, also a winner of the King George VI Chase in 2004 and 2005, was as low as 20-1 to regain the Gold Cup crown.