 Parliamentary boroughs in England ranged widely in size from small hamlets to large cities , partly because they had evolved haphazardly . The earliest boroughs were chosen in the Middle Ages by county sheriffs , and even a village might be deemed a borough . Many of these early boroughs ( such as Winchelsea and Dunwich ) were substantial settlements at the time of their original enfranchisement , but later went into decline , and by the early 19th century some only had a few electors , but still elected two MPs ; they were often known as rotten boroughs . In later centuries the reigning monarch decided which settlements to enfranchise . The monarchs seem mostly to have done so capriciously , often with little regard for the merits of the place they were enfranchising . Of the 70 English boroughs that Tudor monarchs enfranchised , 31 were later disenfranchised . Finally , the parliamentarians of the 17th century compounded the inconsistencies by re @-@ enfranchising 15 boroughs whose representation had lapsed for centuries , seven of which were later disenfranchised by the Reform Act . After Newark was enfranchised in 1661 , no additional boroughs were enfranchised , and the unfair system remained unchanged until the Reform Act of 1832 . Grampound 's disenfranchisement in 1821 was the sole exception . Most English boroughs elected two MPs ; but five boroughs elected only one MP : Abingdon , Banbury , Bewdley , Higham Ferrers and Monmouth . The City of London and the joint borough of Weymouth and Melcombe Regis each elected four members . The Welsh boroughs each returned a single member . 
