Middlesex was a constituency of the House of Commons of the Parliament of England, then of the Parliament of Great Britain from 1707 to 1800, then of the Parliament of the United Kingdom from 1801 until abolished in 1885. It returned two members per election by various voting systems including hustings. Boundaries and boundary changes This county constituency until 1832 covered all the historic county of Middlesex, in south-eastern England, comprising Spelthorne, Poyle, South Mimms and Potters Bar in other modern counties, together with the north, west, and north-west sectors of the present-day Greater London. Apart from the ability of some voters to participate in the borough franchises of the cities of London and Westminster (after dates of their inception, see top right or below), it gave rise to three more urban offshoot divisions in 1832, one of which was split in two at the next national review or reform, in 1868. Its southern boundary was the River Thames. The county seat returned two Members of Parliament (sometimes referred to by the medieval term of knights of the shire). The place of election for the county was until 1700 at Hampstead Heath, thereafter at The Butts in the town centre of Brentford. Hustings were typically over a period of a fortnight when candidates set out their stall, and visible bribery had become not uncommon in closer contests around the country in such larger seats at the time, inspiring William Hogarth’s series of four pictures titled ‘Four Prints of An Election’ (when printed). Until 1832 the county franchise was limited to forty shilling freeholders. The decrease in the value of money due to inflation and the expansion of the wealth and population as the urbanised area in the east around London and Westminster grew contributed to gradually expanding the electorate. The county was estimated by Henning to have about 1,660 voters in 1681. Sedgwick estimated about 3,000 in the 1715–54 period. Namier and Brook suggested there were about 3,500 in 1754–90. The number had reached about 6,000 by 1790–1820, according to Thorne. Close elections between popular candidates would therefore be expensive - the worth of being a local magistrate, major landowner or other dignitary carrying little weight among such a generally urban and numerous upper-middle class forming the bulk of the electorate. For subsequent changes in the franchise see Reform Act 1832 and Reform Act 1867. From 1832 voters were registered;