Henrietta Howard: King's Mistress, Queen's Servant, By Tracy Borman

When George II wanted a lover, he looked no further than his wife's Woman of the Bedchamber. Lucky girl...

When George II was cross – which was often – his face turned crimson, his eyes bulged and he began to stamp, snatching off his wig and kicking it around the room. Short, stout, vain, pernickety and very irascible, he was not an attractive man. Henrietta Howard enjoyed the dubious honour of being his mistress for 16 years. By all accounts, and there are many, this most uxorious of monarchs selected her not as the result of grand passion but because she was discreet – and because he felt that he really ought to have a mistress "as an appurtenance to his grandeur". Besides, as she was also his wife's Woman of the Bedchamber, she was handily available.

The powerful Queen Caroline was, understandably enough, pretty nasty to her (she insisted, for example, that Henrietta knelt to hold the basin while Her Majesty's vast person was washed) yet she retained her services for fear that the King might find a less manageable concubine to replace her. Eventually Henrietta escaped and married – for love – George Berkeley, a charming man with whom she enjoyed 11 years of happiness before lapsing into a long and busy widowhood.

Does such an apparently minor player merit a full biography? Emphatically, yes, for several good reasons. First, the five large volumes of her surviving correspondence provide a source of fascinating insight into 18th-century life, and into the characters of the often famous men and women who were Henrietta's friends. And then, her personal and intimate knowledge of the Hanoverian kings is revelatory, hilarious and shocking (that Bonnie Prince Charlie managed to fail in his endeavour to overthrow such an avaricious and cantankerous bunch is truly astounding). Finally, her own life is as packed with incident as a racy novel. Given her early misfortunes, a lesser woman would have sunk without trace. Henrietta surfaced, took several deep breaths and swam resolutely on.

She was born Henrietta Hobart at Blickling Hall in Norfolk but this promising start in life was blighted by the early loss of both parents, several siblings and any hope of a reasonable income. Having made an unwise marriage to Charles Howard, a notorious gambler, drinker and bully, she soon found herself starving and on the run from creditors, having assumed the unassuming name of Mrs Smith. She tried to sell her long, famously beautiful chestnut hair but the 18 guineas she was offered wasn't enough to settle their debts (though her husband said it was more than she deserved). In a desperate gamble, she scraped together enough money to go to Hanover to seek a place at the court of the man who would soon be the King of England. It worked. The job was no sinecure, but it promised a welcome measure of security.

Tracy Borman handles her voluminous material with easy grace. Her style is often ironic, tending appealingly towards elegant enthusiasm, and her researches have clearly been exhaustive and stimulating. Her book is packed with selective and revealing detail: a giggly friend writes from Tunbridge Wells where there are "all sorts of Diversions but... Ravishing is the most prevailing entertainment"; a cousin complains about the difficulties of travel: "If one could fly in ye Aire, twould be a charming Countrey"; the loathsome and sinister Charles Howard secures a warrant to seize his wife "wherever he might find her".

When, to everyone's relief, Howard suddenly died and Henrietta was finally allowed to retire from court, she was paid off by her royal lover (his gift included "a sett of Guilt Plate") and she built Marble Hill, an exquisite

Palladian villa in Twickenham, near the home of her friend Alexander Pope. He, and many other friends and admirers vied with each other to offer help and advice on its structure and decoration.

These friends come alive in Borman's sketches. Though widely known as "The Swiss" on account of her carefully cultivated neutrality, so clever and kindly was Henrietta that John Gay, Jonathan Swift and Lord Chesterfield were all in her thrall, at various times. Pope, a Catholic, could hope for no position at court and wanted only her friendship, whereas Swift became viciously vindictive when she failed to secure him a post: what he didn't grasp was that Queen Caroline would automatically veto any request from such a source.

Chesterfield wrote to her for years: there's a lovely exchange in the last year of her life, in which he assumes the character of his footman and she replies as if from her Irish maid "Lackaday, Mister Thomas, here have I been turmoilin and puzelin my poor brains to write to a Jackanandy..." She enlisted the help of Horace Walpole, her last and most devoted friend, to write that one.

As for the royal family, their domestic behaviour left much to be desired. By the time George I arrived in England with his two mistresses, he had long since divorced his wife, removed their distraught children from her and imprisoned her for life. Before long, he'd banished his son from court but kept the prince's children with him, one of whom then died. This pattern repeated itself for generations. The House of Hanover, like ducks, make bad parents.

Successive banished princes took refuge where they could, and often set up rival courts. After one of these forced evictions, Henrietta found herself having to look after her royal employers who had fled to a house belonging to their chamberlain. There was – shockingly for those days – not enough room for them to occupy separate apartments. And then they caught chickenpox. Mistress of one, servant of the other, the resourceful Henrietta sat between their two beds, and read them stories until they fell asleep. What a woman.