Paris Hilton’s boyfriend Stavros Niarchos has apparently caused £57,500 damage to a hotel at Kelly Osbourne’s birthday bash.

The party for Osbourne’s twenty-first descended into anarchy after Niarchos started a pillow fight.

The play-fight which followed eventually triggered the water sprinkler system and the Las Vegas’s Hard Rock Hotel had to be evacuated.

It was left in a bad way, a guest said, commenting: “Every lamp was broken and the carpet coated with pillow feathers.???

Hilton, who was upstairs when Niarchos kicked off the action, was furious and shouted: “I don’t want Hard Rock to think I bring in people who do this stuff."