Kings and royal princes were the rock stars of their time – with the rampant sex lives and mistresses to match. Too bad about the murder, blackmail and kidnapping along the way…

Never take a mistress, Your Majesty, it only ends in tears. This one piece of advice should have been given to every British monarch for the last four hundred years – but none of them would have listened.

These kings and princes were the rock stars of their time – women flocked and bowed to them, they could choose whoever they wanted. And as much as they wanted.

Granted, murder, blackmail, grand theft and kidnapping were all part of the bedding of these royal mistresses, but somehow Their Majesties always stood above it all.

Some kings had astonishing numbers of mistresses: King Edward VII had more than seventy known girlfriends, beaten only by his great-uncle, King George IV, with eighty.

Saint George III apparently had none, but still did not escape sexual rumors and innuendo.

One of Edward VIII’s early loves when he was Prince of Wales was Maggie Alibert, a curvaceous courtesan whom he courted in Paris in the closing days of the Great War.

They met at the city’s famous Crillon Hotel and Edward fell so in love that he showered her with a mountain of embarrassing love letters.

Later, Maggie married an Egyptian aristocrat, Ali Kamel Fahmy Bey, but murdered him in cold blood in their suite at the Savoy Hotel after six months.

The couple was on an extended honeymoon and got into an argument after a night out. Maggie shot him several times in the back, using a .32 caliber Browning automatic.

When she went to trial, the judge banned any mention of her challenging past as a courtesan. A secret deal had been struck: Maggie would return the tell-all letters to the Prince of Wales in exchange for not mentioning his name.

And so she was acquitted of the murder charge – clearly a scandalous miscarriage of justice – but at least the future king’s reputation was preserved.

Edward was less lucky when it came to Millicent Milroy, a Canadian schoolteacher who claimed she secretly married him when he visited her hometown of Galt, Ontario, in 1919.

The prince rode into the city on a steam train as part of his tour of Canada.

Fifty years later, the still apparently single Millicent commissioned her gravestone – which still stands to this day – which boldly reads: ‘Millicent… wife of Edward (VIII) Duke of Windsor’.

She wouldn’t die for another fifteen years, but to the end she insisted she was Edward’s secret wife.

Have they met? Did they kiss? Are they married? Nobody knows.

Elizabeth, the Marchioness Conyngham, was a great beauty during the Georgian period and, dissatisfied with her fate, she donned her cap to the Prince of Wales, later King George IV.

It took thirteen years for him to put her to bed, but she felt it was worth the wait – because as he lay on his deathbed in Windsor, Elizabeth picked up as many jewels as she could and headed for the door.

“Despite her beauty, she was considered vulgar, clever, greedy, and unsuitable for aristocratic society because of her common background,” read one description of her.

She was also a thief on a grand scale – among her loot was said to be the whopping large Hope Diamond, one of the largest stones in history at 45 carats.

King George VI, the current king’s grandfather, was a lightweight when it came to the bedroom – with only three or four mistresses before marrying Lady Elizabeth Bowes-Lyon.

But his brothers made up for this lack of sexual ambition: Prince George, Duke of Kent, was NSIT – not safe in taxis – with either sex.

He had a number of gay affairs before his marriage – although not with Noel Coward, as some people claim – but his main interest was in women. Every woman, in fact, and there could be hundreds.

Less successful was George VI’s other brother: Harry, Duke of Gloucester, the deadbeat of the royal family.

He had an affair with aviator Beryl Markham, who convinced him that he was the father of her son. If Harry Gloucester had had the sense to count the months until conception on his fingers (nine, Harry, in case you didn’t know), Beryl would be in Africa and he in Britain.

Nevertheless, the nincompoop paid up after Beryl threatened to take him to court for alimony.

King George III has always been regarded as a saint by royal historians. He fell in love and married Princess Charlotte, with whom he had no fewer than fifteen children. But even this royal paragon did not escape scandal.

At the age of 15, he formed a ‘friendship’ with Hannah Lightfoot, eight years his senior. She had married Isaac Axford in 1753, but went missing within a year and was never discovered again.

Word spread that George, then Prince of Wales, had her kidnapped and secretly married her, their marriage producing three children. No one has ever proven that – but no one has ever discovered what happened to Hannah, so the jury is out.

Royal women were just as prone to sexual dalliances. Everyone knows that Queen Victoria was closely associated with ghillie John Brown, but she was equally attracted to her Indian servant Abdul Karim, whose photo was hidden in her coffin on her orders when she died.

But it is Queen Caroline, wife of King George IV, who was the sexual pioneer with at least 19 notches on her bedpost.

According to expert historian Anthony Camp, Caroline – who thought George was so ugly that he reached for the brandy decanter when he was first confronted by his future wife – had no trouble finding bed partners. Among them were British Prime Minister George Canning, an Italian singing teacher Pietro Sapio and Joachim, the King of Naples.

But when it comes to bad behavior, perhaps the last word should go to courtier Ralph Montagu, who boldly bedded both mother and daughter in Paris. First came Barbara, Duchess of Cleveland, mistress of King Charles II, after her moments of passion with His Maj were over.

Concerned about the virtue of her daughter Anne (the king’s illegitimate daughter), the Duchess had her placed in a convent for safekeeping.

But the moment she left for England, the predatory Montagu stormed Anne, sprung her from the convent and began a steamy affair. He was 38, she was only 15.

Montagu, who would become the first Duke of Montagu, was truly a bad boy. Ambitious and a spendthrift, he kept himself comfortable by seducing wealthy widows; his last victim was Elizabeth, Duchess of Albemarle.

Elizabeth, supposedly mad, had vowed to marry only a crowned head after her husband’s death – so Montagu tried to woo her, disguised as Emperor of China.