Stella McCartney launched into an explosive rant after reading newspaper reports about stepmother Heather Mills.

The fashion designer lashed out at her father Paul last weekend when a tabloid reported Mills' alleged claim that he used to hit his late wife Linda.

"Paul kept pleading with her to calm down - but she couldn't," a source told the News of the World. "She wanted to go straight to see Heather, but he said, ‘You can't go anywhere in that state'. He had to stand in front of the door and stop her. He was pleading with her. It was a heartbreaking scene."

The relationship between Stella and Heather was frosty from the beginning, even after Paul took the pair on a night out together in 2002.

"He was adamant they should be one big happy family - he didn't realise how wrong he could be," the insider added. "From what Stella said to friends she told her stepmum she was a money-grabbing bitch and Heather hissed at her to mind her own business.

"The upshot of a very frosty evening was, ‘You keep out of my way, I'll keep out of yours'. It broke Paul's heart."