In “Long Live the King,” which continues the trilogy that began with “Habits of the House,” Fay Weldon further explores the disparate worlds of “them that has and them what serve ’em.”

Weldon has written award-winning novels and plays and was also a screenwriter for the television series “Upstairs Downstairs.” She remains at the top of her game with her new book. Set in 1902, the novel continues the saga of the Hedleigh family of London’s posh Belgrave Square. There is Robert, Earl of Dilberne; his wife, the Countess Isobel; their offspring, Lord Arthur and Lady Rosina, and numerous servants.

Like all of London society, the earl and countess are caught up in the lavish preparations for the coronation of the new king, Edward VII: “Bertie, Prince of Wales, ascended the throne on the death of his mother, Queen Victoria. Her reign had lasted 63 years. The shock to the country was great, the more so since it now saw Bertie as a voluptuary, a drunkard and a gambler.”

The novel is replete with amusing plot twists, one of them centered on the earl’s 16-year-old runaway niece, Adela. Another concerns the beautiful Consuelo Vanderbilt, the Duchess of Marlborough. She has been selected to be Mistress of the Queen’s Robes, an honor indeed. But Isobel frets that Robert will be unfaithful: “She had a kind of waking vision of Consuelo’s curly black head burrowing into Robert’s naked [chest.]”

Fans of “Downton Abbey” will relish this rich and witty comedy of manners.