Tourists enjoying a day of sightseeing at Windsor Castle got more than they bargained for today when a couple were caught having sex on the Queen’s lawn.

Ignoring signs asking visitors to Please Keep Off The Grass, the man and woman, said to be in their early 30, selected a spot near the castle’s Garter Tower and stripped off in full view of hotels, pubs and shops.

An employee at the Harte and Garter Hotel, which overlooks the castle, said guests went out to observe the scene and could not believe their eyes. The woman, who asked not to be named, said: “People were shouting things like ‘what are you doing?’ but the couple didn’t seem to care at all. It was going on for about 10 or 15 minutes, which is quite a long time, considering the location.”

Another witness, Mark Robinson, 44, said the couple carried on until police intervened. He said: “The officers told them to stop and the sight of the uniforms seemed to snap them out of it. They were unsteady on their feet and the guy pulled his trousers up and helped the girl put hers back on.

“The Japanese tourists were comparing their videos.”