Does a practical joke differ from a hoax? It could be a matter of scale. Anyone can deploy a whoopee cushion, but it takes rather more — as Virginia Woolf and others did, long before Ali G — to kit oneself out as Abyssinian royalty for a 1910 state visit by train to the deck of a dreadnought in Weymouth harbour. There was nothing in it for them, but that hoax brought questions in the Commons. Monetary gain, as with the Hitler Diaries, certainly sours claims for hoaxes as a pure art form.

Where does this leave the humble,twentysomething mother-of-three Mary Toft, and those around her? The question is raised by Karen Harvey’s brief but amply detailed study of a woman who, in 1726, brought the Surrey market town of Godalming publicity it had not known before. Her story occasioned numerous contemporary publications, several unflinching engravings by Hogarth, a ballad by Alexander Pope and even aroused the curiosity of George I. Yet nowadays most are unfamiliar with the case. The details invariably bring a horrified yelp.

Put simply, Mary, a field labourer, gave birth to rabbits — 17 times. Naturally, none survived. Word spread locally. A doctor, John Howard, witnessed and even induced some of these extraordinary productions, and attested to their monstrous veracity. The Royal Household’s surgeon visited, as did the Prince of Wales’s secretary. The King requested Mary be brought to London, where she was installed at a bagnio in Leicester Fields (as was). There, recumbent, she was studied sedulously by eminent doctors. Pamphlets and articles proliferated; of rabbits there were no more.

With Mary’s humiliating installation at the bagnio, the scandal really blew up. The publicity helped the owner with his cash-flow problem, while the city was torn by faction, and the press — thousands of newspapers across England — seethed with speculation and vituperation.

That December she confessed to concealing parts of various animals (including a hogshead) about her person before heaving them into the world. For this she was sent to the Bridewell and, pending trial, suffered hard toil and grim health before release without charge, return to Godal-ming and obscurity. This book’s title is the parish register’s entry when she died in 1763. She had not committed a criminal act. But that anybody should have believed her story at all is extraordinary. Still, as Pope’s ballad put it: ‘E’er since Days of Eve,/ The weakest Woman sometimes may/ The wisest Man deceive.’

Harvey fills out the case fascinatingly, to create a view of the country and city in a shifting era. The local scene entails such matters as the decline in clothing work, the siting of the town clock to ensure that workers were not late, and the sandy soil’s being ideal for rabbits, a creature no longer considered wild but part of a landowner’s property, which here included commercial warrens. The consequence of this change in rules on rabbit ownership was bad feeling and court cases.

Everything took place against fears for the social order, and the Whigs and Tories would wrestle each other for control of the constituency for decades. Was Mary subverting the natural order? Was she perpetuating witchcraft in the face of the Enlightenment? Tall orders for somebody described by one doctor as ‘of a very stupid and sullen temper’. Pope claimed of one rabbit that a surgeon ‘slyly thrust it up’. Harvey convincingly portrays Mary’s mother-in-law as a main player in the hoax.

Mary had suffered a miscarriage shortly before the rabbit brouhaha, so her lactating breasts gave the hoax plausibility. And this was when ‘the 18th-century body — whether male or female, young or old — did not give up its truths easily. The internal workings of the live human body were impossible to observe.’ Many still believed a pregnant woman’s wild imaginings could become imprinted upon her foetus.

Harvey’s prose is dry, but so is a good martini; and her extraordinary narrative will surely be savoured by a wide audience.