Prince Andrew, the Duke of York, made good on a promise today and rappelled down the face of the 306-meter Shard, the tower under construction in London. The Prince and 40 other daredevils made the descent to benefit charity.

"It was nerve-racking,” the 52-year-old Prince told reporters. "And I was stepping over the edge, somebody said, 'by the way, there is quite a lot of condensation and the windows are slippery so you may just slide.’

"And he was right - I just slid for the first, whatever it was, 10 or 15 floors."

Prince Andrew and the “royal posterior”—as The Guardian phrased it—began his descent from the 87th floor and finished on level 20. He became the first member of the Royal family to abseil down what will be Europe’s tallest building, “although, to be fair, there wasn’t a great deal of competition,” the Daily Mail points out.

The Prince will remain in rare company--future abseiling on the Shard has already been banned.

The stunt reportedly raised about GBP300,000 for the Outward Bound Trust and the Royal Marines’ Charitable Trust Fund.

Watch footage from the Duke's helmet-cam and descent below.