24/02/2012 05:29 GMT | Updated 25/04/2012 06:12 BST

'Dancing On Ice' Coach Karen Barber 'Livid' With Judge Katarina Witt

The atmosphere in the Dancing On Ice studios is getting frosty - head judge Karen Barber is reportedly on the verge of a bust up with co-star Katarina Witt.

Katarina has made few friends since she started on the show thanks to her scathing comments and cruel remarks, and a furious Karen is said to be at the end of her tether with the new judge.

Last weekend, millions of viewers saw Karen shooting evil glares at Katarina and it seems the series may soon take a turn for the worse.

A source close to the show told The Mirror: "Last weekend's scores and comments were exceptionally hard on the contestants, and most of the scathing comments came from Katarina.

"Karen was furious during the show - everyone could see her glaring angrily at Katarina.

"But things escalated off camera. She thinks Katarina is nasty rather than supportive.

"She's determined to defend the contestants who are trying their best, and Karen takes some of that criticism personally."

Karen was controversially axed from the panel in 2010 and was given the role of head coach.

The insider continued: "There's no love lost between Karen and Katarina and the atmosphere is becoming increasingly tense - she's threatened to have serious words with Katarina if necessary.

"It's getting very fiery, but the politics of the show are also a big issue. Deep down, Karen would rather be on the panel herself."

And Karen isn't the only person Katarina has upset - former contestant Heidi Range recently revealed she felt singled out by the German skater, who accused the Sugababe of relying too much on skating partner Andrei Lipanov.

Speaking to The Sun, the pop star said: "It was unfair because it was never said to any of the other girls, 'Oh, he puts you in your lifts...' With the other girls it was always acknowledged what they'd done to hold themselves and get into that lift.

"But with mine she seemed to dismiss how much effort I put into them. You have to go for it and hold yourself in there and it is terrifying. It was never said to any of the other girls.

"I took it personally because it was a point she made every week."