Elizabeth married Sir Peniston Lamb MP in 1769 for his money. He inherited £1 million – worth about £125 million today - from his father, a get-rich-quick lawyer, the year before their wedding when he was 23 and she was 17. His inheritance included £500,000 in cash and two country estates at Melbourne Hall in Derbyshire and Brocket Hall, Hertfordshire.

Colin Brown

Colin Brown

Sir Peniston was a wastrel who fell in love with Sophia Baddeley, a singer and high class escort within months of being married to Elizabeth. He lavished part of his fortune for her sexual favours including jewels worth £171,000 today and even a horse.

Lady Melbourne had six children and only one, her first son, Peniston, was by her husband. Her second son, William Lamb, born in 1779 was by her long-term lover, the Earl of Egremont, who was alleged to have “bought” Lady Melbourne from another lover for £13,000.

William Lamb, the future Prime Minister, was almost certainly conceived in a field at a military camp of 15,000 men on the rolling Downs of Kent. High society ladies went on night-time manoeuvres with the men in the tents. There were so many sexual scandals that the camp became notorious in London. It was appropriately called Cocks Heath.

Georgiana, the famous fashionista, Duchess of Devonshire, was so in awe of Lady Melbourne, her most intimate friend, she addressed her in letters to “Dearest Them” after Themis, the Greek Goddess of Justice.

Melbourne, the state capital of Victoria in Australia, was originally called Batmania by the settlers after their leader, John Batman. It was renamed in 1837 after the family title when the Second Viscount Melbourne was Queen Victoria’s Prime Minister. His title was taken from the family estate in Melbourne, Derbyshire.

Melbourne House in Piccadilly where Elizabeth hosted a glittering Whig salon cost at least £60,000 to build and furnish in the latest fashion – the equivalent of more than £7 million today. The building off Piccadilly is now flats called Albany and is still one of the most prestigious addresses in London.

The fat Prince of Wales fathered Elizabeth’s fourth son, George, named after him. Her husband was made a royal courtier in 1783 as a Gentleman of the Bedchamber by the Prince in 1783 – nine months before George was born. When he became Prince Regent he granted what Elizabeth had always wanted - an English hereditary peerage for her husband with a seat in the Lords.

Lady Melbourne was known as ‘the thorn’ for her sharp tongue, and accused of plotting like the Marquise de Merteuil in Les Liaisons Dangereuses. She persuaded Byron to marry her niece Annabella Milbanke to break up his love affair with Lady Caroline Lamb, her son William’s wild wife. Lady Melbourne did not tell Annabella that Byron had already had an incestuous love affair with his half-sister.

Lady Melbourne was addicted to opium – laudanum - prescribed by her doctor to relieve excruciating pain in her limbs. She died in 1818 at the age of 66. She was buried at St Etheldreda’s Church, Hatfield, near Brocket Hall, but the family tomb was forgotten over time. Her rivals, the Cecils, have a Tudor tomb in the church, but today the Melbournes have only a small plaque dedicated to her son William.