Mabbott was commissioned in the navy as a lieutenant in 1711,
Egmont, about 1750, drawing up for the Prince of Wales plans for a future Parliament, placed Mabbott among persons to be brought in by the new court, and referred to him as ‘Governor Mabbott’. Next, Mabbott became connected with Henry Fox, who, when a vacancy was imminent at Liverpool in 1755, named him to the Duke of Newcastle as a ‘good and proper’ candidate.
If your Grace will now engage for what it shall exceed [£]1,000, Mr. Mabbott bids me say that he shall look upon himself as under strong obligations to espouse your Grace’s interest on every honest occasion.
Newcastle doubted whether the King would allow him to engage in this affair. ‘If I should have a negative, we may find out some way to indemnify Mr. Mabbott ... When we agreed upon Mr. Mabbott, there was no notion of his limiting the expense, much less to so small a sum as £1,000.’
On 19 Apr. 1757, during the Duke of Devonshire’s term at the Treasury, Fox wrote to him when forwarding applications for a share in the loan: ‘Mr. Mabbott, a Member of Parliament and a very rich man desired more, but I have put him down for £40,000’—which Devonshire scaled down to £30,000, with ‘40,000?’ against it.
No vote or speech by Mabbott is recorded but presumably he supported Government. He did not stand again in 1761, and died 14 Nov. 1764. He left his property to his wife for life, and then to her daughter by her marriage with Coates who was the wife of P. C. Webb.
