The yeomanry was first used in support of local authorities to suppress civil unrest , most notably during the food riots of 1795 . Its only use in national defence was in 1797 , when the Castlemartin Yeomanry helped defeat a small French invasion in the Battle of Fishguard . Although the Volunteer Corps was disbanded following the defeat of Napoleon in 1815 , the yeomanry was retained as a politically reliable force which could be deployed in support of the civil authorities . It often served as mounted police until the middle of the 19th century . Most famously , the Manchester and Salford Yeomanry was largely responsible for the Peterloo Massacre , in which some 17 people were killed and up to 650 were injured , while policing a rally for parliamentary reform in Manchester in 1819 . The yeomanry was also deployed against striking colliers in the 1820s , during the Swing riots of the early 1830s and the Chartist disturbances of the late 1830s and early 1840s . The exclusive membership set the yeomanry apart from the population it policed , and as better law enforcement options became available the yeomanry was increasingly held back for fear that its presence would provoke confrontation . Its social status made the force a popular target for caricature , particularly after Peterloo , and it was often satirised in the press , in literature and on the stage
Peterloo Massacre
Peterloo Massacre
Yeomanry Cavalry