It was meant to be a glorious celebration of happier times for the royals.

It was 1969 and a young and rather gawky-looking Prince Charles was set to be invested as the Prince of Wales amid much pomp and ceremony.

And who better to commemorate a milestone in British royal history than the nation's greatest living artist, Bradford-born David Hockney.

And so the celebrated American magazine Time commissioned him to produce several works of art that would grace the cover of a special edition.

But the commissioning editors weren't quite ready for what they saw.

Instead of portraits of royal glory, they received a series of pictures that showed him in a less than flattering light - and in some cases barely recognisable.

Instead of regal majesty, the pictures highlight his more prominent features.

In one image, brightly rouged cheeks give him the appearance of a pantomime dame. In another, he bears an uncanny resemblance to Spock from Star Trek, while in all of the drawings, his ears are startlingly large.

One pencil sketch appears so rough and ready that Charles is unrecognisable, even in caricature.

The less-than-flattering caricatures of the heir to the throne did not appear on the cover and the work of another artist was used instead.

Now the seven works have surfaced from a private collection to appear at a Christie's post-war art sale at King Street in London on February 7.

Sold as one lot, they are expected to fetch up to £70,000.