The part played by the prime minister’s “maîtresse-en-titre” Carrie Symonds in the departure of Dominic Cummings, and the defenestration of his ally – Downing Street’s combative Communications chief, former chicken Lee Cain – has fascinating historical parallels. (It may be ungallant to call Ms Symonds a mistress, given her official title as Boris Johnson’s “fiancée”, but there seems to be no imminent sound of wedding bells for the happy couple.)

Throughout history, the mistresses and wives of kings and rulers have often played a prominent, if backstage, part in the politics of patriarchal regimes, and it is noticeable that such ladies are usually found to the fore when these regimes are in the palsied hands of male rulers on their last legs. So, it may prove to be the case with the fatally flawed rule of the House of Johnson.

The private dalliances of illicit love affairs often have an influence on great public events

King Edward III was one of the greatest mediaeval monarchs. During the first half of his fifty-year reign, he defeated the French at Crecy and Poitiers, seized Calais, weathered the Black Death, and restored law and stability after the disastrous reign of his father Edward II. But during the second half of his rule, the ageing king fell under the baleful influence of his young mistress, Alice Perrers. Purely coincidentally, the king was the same age as Boris – 55 years old – when the 18-year-old Alice became his paramour.

Alice was a business whizz and used her hold over the doting king to acquire huge tracts of land and riches, making her the wealthiest woman in England. Geoffrey Chaucer is said to have modelled the grasping Wife of Bath in his Canterbury Tales on Alice, and there is a distinct resemblance between Edward III and “January”, the old fool in Chaucer’s “Merchant’s Tale” who is blind to the faithlessness of “May”, his teenage bride who is surely a portrait from life of Alice.

Incapacitated by age and sickness, Edward did nothing to curb his acquisitive young lover, who intimidated courts and judges when they tried to check her excessive greed. Only after the king died from a stroke, were the authorities able to move against Alice, and regain at least some of her dubiously acquired property. Edward and Alice’s legacy left an impoverished and chaotic kingdom which within a few years erupted in the Peasants’ Revolt, and finally in the dynastic struggle we call The Wars of the Roses.

Those wars produced two strong women who became rival queens as the Lancastrian and Yorkist factions fought and finally destroyed each other in fratricidal strife. Margaret of Anjou, wife to the feeble-minded Henry VI, propped her hopeless husband on his tottering throne, refused to admit defeat despite repeated lost battles, and ended as the sole champion of the Lancastrian cause.

Carrie’s goal is to re-package the prime minister as a softer, cuddlier Boris

Margaret’s counterpart was Elizabeth Woodville, a blonde beauty who ensnared the womanising “Sun of York” Edward IV. So strong was Elizabeth’s hold over the king that she was accused of sorcery. She brought in her wake a whole tribe of grasping siblings who forcibly married themselves into an appalled aristocracy and helped themselves to generous portions of power and wealth. As the strapping six-foot king declined into obesity, lechery, and laziness with another mistress, Jane Shore, so the grip of the Woodvilles on the kingdom tightened.

The result was the bloody coup and short reign of Edward’s brother, the murderous Richard III, who not only disposed of the Woodvilles in short order but became the last king of the mighty Plantagenet dynasty when he was butchered at Bosworth by the upstart Tudors. Henry VIII’s problems with mistresses who became wives are too familiar to require reiteration, and another ladies’ man monarch, Charles II, is as well known for his myriad mistresses as he is for his spaniels and spell in an oak tree.

Charles was so indolent that – like Johnson – he allowed his mistresses to interfere in politics. His own principal whore, the corrupt Barbara Palmer, Duchess of Cleveland, was directly responsible for the dismissal of the king’s most capable minister, Edward Hyde, earl of Clarendon; and his later mistress, Louise de Kerouaille, was inserted into his court as a paid French spy. Charles’s brother and successor James II shared his taste for mistresses and his chaotic rule culminated in his overthrow and the end of the Stuart dynasty.

France, of course, was well used to the rule of the mistress. Diane de Poitiers entranced King Henri II when she was thirty-five and he was a teenager. He remained in thrall to her for the next twenty-five years and showing off to her at a tournament indirectly caused his agonised death in 1559 when a splintered lance pierced his helmet. What followed was the ruinous wars of religion as France tore itself apart in civil strife and massacres between Catholics and Protestant Huguenots.

The end of the monarchy in France was presaged by the rule of Madame de Pompadour, “maîtresse-en-titre” to King Louis XV in the mid-eighteenth century. Like Diane de Poitiers, La Pompadour built a network of clients, patronised the arts, constructed chateaux and generally identified the Crown with waste and frivolity, inevitably leading, as night follows day, to the upheaval of the great revolution of 1789 and all the ills that followed.

The private dalliances of illicit love affairs often have an influence on great public events out of all proportion to their apparent triviality. Charles Stewart Parnell’s adulterous passion for Katherine “Kitty” O’Shea, for example, was not only the great scandal of late Victorian Britain but crippled the cause of Irish independence and unity up until the present day. And the elderly H.H. Asquith’s drooling love letters to his girlfriend Venetia Stanley, written in Cabinet meetings at the height of World War One, certainly distracted the prime minister from efficiently directing the war and helped lead to his ousting in December 1916 by his party colleague David Lloyd George.

The “Welsh wizard” himself was no stranger to extra-Marital dalliance, as his other nickname “The Goat” attests. His own “maîtresse-en-titre”, Frances Stevenson, not content to be a mere appendage to her boss and lover, was the first woman to attain real power in Downing Street as LG’s political secretary and advisor, as well as his bedmate. Their thirty-year affair culminated in marriage after his wife died.

So, what will be the political result of Carrie’s successful coup against Cummings and Cain? Her goal is said to be to re-package the prime minister as a softer, cuddlier Boris in the New Year after a likely fudged Brexit. She will have her work cut out. Johnson might be a prime minister for good times, but in a crisis of the current magnitude he is out of his shallow depth and not waving but drowning. Deprived of two of the men he has relied upon to do his heavy lifting, he is a sawdust Caesar: on his own and dependent on the distaff help of his latest lover.

For the sad truth about the PM that Covid-19 has brutally exposed is the same that Clement Attlee laconically articulated when sacking one of his ministers. Asked by the puzzled man why he was being fired, Attlee simply answered: “Not up to the job. Good afternoon”.