A photo marked "not to be published" that shows a teenage Diana Spencer before she became Princess of Wales has been sold by a US auction house for more than 18,000 US dollars (£11,400), Belfast Telegraph said.

The photograph shows a group of friends relaxing during a ski trip, with Diana reclining on a bed, with a young man seated behind her and a bottle of whisky on the window sill.

It was acquired by a British newspaper just after her engagement to the Prince of Wales, but someone at the paper wrote "not to be published" across it, presumably because it would have embarrassed the royal family.

RR Auction in Amherst, New Hampshire, says the photo sold in the online auction to a property investor from San Diego for 18,306 dollars, well above early estimates.