Princess Beatrice has said she wept with joy after conquering the summit of western Europe's tallest peak, Mont Blanc.

The 24-year-old told Hello! magazine she suffered a fit of "constant nervous giggles" when she first arrived for her adventure, with friends including Holly and Sam Branson, and their father, Virgin tycoon Richard.

After tackling the climb she said: "The summit was like a dream. It was so overwhelming I began to cry with joy for making it to this magical world at the top of Europe."

She posed on top of the peak for the magazine with her fellow climbers, with whom Beatrice  ran the 2010 London Marathon roped together as a giant caterpillar.

"I was tired and the altitude brought my feelings to the surface," she says. "I broke down in tears and truly didn't know if I was going to get down. The delight of making it to the bottom was so overwhelming that I couldn't speak. I have never felt such joy and excitement of such a sense of achievement."

She and her friends used the climb to launch their new charitable venture, Big Change.