St. John served in the West Indies and the Channel Isles until 1783. He was provided with £240 p.a. out of his father’s secret pension of £1,200. The supply was cut off by Bolingbroke’s death in 1787, when St. John’s uncle the 4th Duke of Marlborough tried to induce the prime minister to compensate him somehow.
St. John had fallen out with Lake in India, which resulted in his misconduct. A court of inquiry ‘came to no decision or opinion’, but the commander-in-chief’s view reflected on St. John’s ‘personal courage’ and prejudiced his prospects of employment and of recognition of his services. His cousin Lord Pembroke described him to Lord Bathurst, 10 Oct. 1809, after the latter had attempted to do something for him, as ‘an innocent and injured man’, sacrificed not so much ‘to party’ as
to his own vapouring vanity which sometimes entertains and amuses us who know him in private life, but which is never forgiven by men of narrow minds and low understandings at home and abroad, whose characters or proceedings he has loudly meddled with, in some measure to gratify that same vanity, and as the strong only are merciful, I see no end to his persecution. Amen.
The King advised against reopening inquiry into St. John’s conduct.
In 1818 St. John was returned for Oxford after a contest, his cousin the 5th Duke of Marlborough seizing an opportunity to restore the family influence there.
St. John died 19 Nov. 1844, the second senior general in the army.
