In the early eighteenth century the principal interests at Marlborough were in Charles Seymour, 6th Duke of Somerset, Whig, and the Bruce family of Tottenham Park and Savernake, Tories. The Bruces had succeeded to the ancestral Wiltshire estates of the Seymours by marriage in 1676; the Duke owned Marlborough Castle. The franchise was in the corporation, a close body, recruited by co-option.

Between 1711 and 1714 there was a dispute over a bye-law regulating the method of choosing a mayor, leading to lengthy legal proceedings. Rival mayors were installed in office, John Fowler, representing the Bruce interest, and Roger Williams, representing that of the Duke of Somerset. Before the 1715 election the Duke let it be known to the corporation that owing to illegalities in choosing mayors, the Marlborough charter was likely to be forfeited and they themselves heavily fined. To settle the matter he proposed a compromise

desiring them to give one vote as the Duke shall direct, and that then all the law shall be at an end, and that Mr. Williams shall deliver up to [Fowler] the maces, seals, and all charters and writings, and that the Duke will be ready to serve the burgesses on all occasions and invites them down to the castle.

The proposal was rejected. Shortly before polling day Lord Bruce’s agent wrote to him on 14 Jan. 1715:

I am very sorry for all the expense at Marlborough ... Less than 20 guineas a man will not content them for this election, because many of them have been offered much more for one vote, besides it may make them very steady for another election.

After the poll Williams, who had got possession of the precept, returned Somerset’s candidate, Sir William Humfreys, jointly with Joshua Ward, a man of straw, who had received no votes. The rival mayor, Fowler, sent an indenture to the sheriff subscribed by 29 burgesses in favour of Bruce’s candidates, Gabriel Roberts and Francis Hayes, who petitioned against Humfreys and Ward. On petition the matter was compromised, Hayes withdrawing, while Ward did not appear before the elections committee, who found Humfreys and Roberts to have been duly elected.2

Thenceforth the Duke’s interest was looked after by his son, the Earl of Hertford, who occupied the castle. For the 1722 Parliament Lord Hertford was himself returned, with Gabriel Roberts, but elected to sit for Northumberland, leaving the vacancy to be filled by Thomas Gibson, Walpole’s man of business. Gibson shared the representation with the Bruces till 1734, when Lord Hertford put up two London business men strongly supported by Walpole, who were defeated by Bruce candidates. While a petition against the return was pending, Hertford wrote to Walpole:

I don’t doubt but by your help to carry my petition for my two Members, and then to secure the corporation for ever, so therefore to shew the town that my interest is not so despicable I must desire that the two companies [of troops] now at Hungerford may be sent hither, which will be no burthen for we have above forty public houses and it will be of great use to my interest, the keeping up of which is a great expense to me but I will keep it as long as I have any money, but this trifle I now ask must be granted me, for if I am not supported I must give it up, and also the few honest men we have amongst us and this I am sure you will not let me do.3

The petition sought to disqualify eleven of the Bruce voters. This depended on the validity of the election of one of the common council, named Bell, which had been confirmed by legal proceedings in the King’s bench. Edward Harley, a Tory, describes the proceedings on the petition.

The counsel for the sitting Members objected that such evidence should not be given at the bar of the House, where the witnesses are not examined upon oath, and when Bell’s election was confirmed by a verdict in the King’s bench by 12 men upon oath and by witnesses proving the same upon oath.

The House decided by 176 votes to 172 that this evidence should be heard.

The next day witnesses were examined who confirmed Bell’s election to have been good. Sir R. Walpole in a long speech laboured to show the contrary and to work up his creatures to a division, but the master of the rolls, Sir Joseph Jekyll, had spoke so very strong on the other side and showed the injustice of setting Bell’s election aside, and the bad consequences of hearing evidence at the bar contrary to a verdict, that Sir Robert, finding he could not spirit up his tools, gave up the question. And it was resolved that Bell was duly elected a common council man without any division. The sitting Members were afterwards voted duly elected. This was a great blow upon the Court, and especially on Lord Hertford’s interest in this borough. For this verdict being confirmed and the 11 burgesses established, Lord Bruce has obtained the borough.4

So it proved, for in 1741 and 1747 Bruce candidates, including the Tory Jacobite leader, Sir John Hynde Cotton, were unopposed. According to a state of the borough supplied to Pelham in 1753 most of the corporation were Bruce nominees.

They have hitherto received a command on all necessary actions, have submitted, and found themselves £50 per man the richer for it, which failed, however, of giving them the same satisfaction that it might have afforded, if there had been any kind of civility or solicitation mixed with the order, which was generally too peremptory.5