For over a century the representation of Carmarthen was almost monopolized by the Vaughans of Golden Grove, Whigs, whose family represented it in most Parliaments from 1621. This hegemony came to an end with the death in 1724 of Richard Vaughan, who had held the seat since 1685. He was succeeded by James Phillips, the son of a local alderman, who was defeated in 1727 by Arthur Bevan, recorder of the borough. Phillips petitioned but gave up when the House of Commons decided that the right of election was in the freemen, rejecting a motion that it was also in the inhabitants.1 The corporation records show a split in the common council between the supporters of Phillips, a Tory, who died in 1730, and Bevan, a Whig, who was re-elected unopposed in 1734.

Between 1738 and 1740, 200 new freemen were admitted, by means of whom in 1741 John Philipps of Picton Castle, the head of the south-west Wales Tories, defeated Griffith Philipps, a local Whig.2 Griffith Philipps petitioned but withdrew his petition on 3 Feb. 1743, apparently as part of a general compromise, since petitions relating to Pembroke county and boroughs, and Haverfordwest were all withdrawn on the same day.3

At the corporation election of 1746 each side elected a mayor and two sheriffs, with the result that for the next eighteen years there were two rival corporations, one Tory, controlled by Philipps of Picton Castle, the other Whig, controlled by Griffith Philipps, each claiming to be the legal one. The election writs were sent to the Whig corporation, thus enabling Griffith Philipps in 1747 to return Admiral Mathews, on whose death in 1751 he returned himself unopposed.4 The 2nd Lord Egmont wrote of Carmarthen in his electoral survey, c. 1749-50:

I hear Sir John Philips is entirely lost here which is not bad. That one Griffith Williams or Philips a Whig but not well with the Pelhams has the leading interest. He should be early applied to.