Hume Campbell’s politics were influenced by three considerations: jealousy of Argyll (Islay) as ‘viceroy’ of Scotland, family pride, and devotion to his brother. For most of the period 1734-1754 he was in opposition, during which time he also built up a considerable practice at the English bar.
In the 1754 Parliament Hume Campbell almost at once ‘took a very active part ... in support of the King’s measures’,
Hume Campbell ... made me an absolute offer of himself, to quit his profession entirely ... to apply himself singly to the House of Commons, to take an active part in everything and to have difficulties in nothing. His condition was to be made chancellor of the duchy of Lancaster with the salary ... made up to £2000 a year ... It is certain he will be of vast use in the House of Commons. His manner of talking is what we want at present.
With the King, however, ‘Hume Campbell would not go down at all’.
Unless Mr. Hume Campbell shall come to me and ask my pardon ... I shall think myself obliged to oppose this promotion to the utmost of my power, for though I can connive at many things I cannot submit to be insulted.
Hardwicke having been placated, Hume Campbell on 9 Dec. was offered the place of lord clerk register with a salary made up to £2,000 p.a.;
The Duke of Newcastle ... had selected another champion who was equal to any philippic and whom he would for that purpose have made paymaster if Fox had not withstood it. This was Hume Campbell, who for some time had deserted Opposition and almost Parliament and applied himself entirely to his profession of the law, which he was at once formed to adorn and suit, for he was eloquent, acute, abusive, corrupt, and insatiable.
Hume Campbell’s ‘masterly speech’ provoked Pitt to a savage personal attack upon the ‘servile lawyer’, once his intimate friend.
According to Walpole,
On Fox’s resignation the brothers were ‘disconcerted with the change of ministry’
The difficulty still rests ... in finding proper persons to carry on ... the business of the House of Commons ... I thought Sir George Lee and Mr. Hume Campbell had been more sanguine upon that essential point ... though ... I doubted their forces for it ... I perceive now that both these gentlemen draw back as to undertaking [it] independently of Mr. Fox.
In the final settlement of the Pitt-Newcastle coalition Hume Campbell received no office; deeply chagrined, the brothers returned to Scotland and began ‘an extraordinary correspondence’ with Newcastle, ‘full of professions outwardly, but really most severe reproaches, not unmixed with threats’,
Mr. White fears ... that Lord Halifax will be set at the head of a connection of weight and ability in which ... Lord Marchmont will join as well as his brother, upon the plan of opposing Pitt as distinguished from your Grace.
When the ministry reached a settlement with Halifax, Dupplin thought the brothers would now ‘change their language’:
Their chief apprehension is of a defeat (and what they will think a disgrace) in the county election ... Mr. White says that Lord Register will never forgive Pitt’s personal abuse and all that can be expected is to keep them quiet, which they may possibly be when they see no standard set up to which they can resort.
Hume Campbell, perforce, renewed his attachment to Newcastle,
He died 19 July 1760. Hardwicke commented to Newcastle, 22 July:
I rejoice in no man’s death but I hope your Grace has not suffered great loss in Mr. Hume Campbell. He certainly had abilities of a certain sort, but I fear he had no principles or courage. You have tried him in this united Administration and had tried him before ... Have you found any real use for him in either?
