Crowds were shell-shocked as they watched the drunken pair stripped and got down and dirty on a private grass bank at Windsor Castle, where Her Majesty was in residence.
The kinky pair was in action for 20 minutes before armed Royal Protection Squad officers stepped in to take down their particulars, reports The Sun.
The pair romped in daylight beneath the castle’s Garter Tower. Some onlookers cheered them on while others shouted “disgusting” and called cops.
The couple was described by police as respectable people with respectable jobs.
Witness Sue Cook, 24, said: “I expect when the woman woke up the next morning she died of shame. She’s a p0rn star now.”
The lust-filled lovers were aged in their early 30s.
A Windsor Castle source said: “The Queen was in residence at the time, but her private apartments are at the other end so she would have been blissfully unaware of it.
“She was not particularly amused when some years ago a couple were caught bonking in a tree in her back garden – Windsor Great Park.”