The son of a wealthy merchant and East India Company director who ‘even exceeded Elwes in penury’, Newnham got £12,000 as his portion and set up business in succession to his brother Thomas as a sugar grocer, with another brother William, at 33 Botolph Lane, Eastcheap (1774). By 1780 he had ceased to trade with his brother, but when the latter was drowned in 1781 succeeded to his fortune and was co-founder of the bank of Newnham, Everett, Drummond, Tibbets and Tanner of 65 Lombard Street (1785), afterwards of 9 Mansion House Street (1791).
In 1791 his banking partner Thomas Everett put Newnham up against the Sydney interest at Ludgershall in a by-election, but Everett’s interest was not then strong enough to return him. In March 1793 he was nominated by the Whigs in the London by-election; but by then he had become an ‘alarmist’, prepared to renounce his political past. Once this was clear, ‘his old friends ... in turn deserted him, and his new friends not choosing to support him, he was without a single uplifted hand in his favour, and left the hall with the strongest marks of disapprobation from the audience’.
Newnham made it clear in his first speech after his re-election, 31 Jan. 1794, that he had renounced his Whig allegiance in favour of the support of ministers during the war against revolutionary France. That this was not an unquestioning support was shown by his speech and vote for inquiry into the inadequacy of convoys for the merchant navy, 18 Feb. 1794, but by and large he thought he had been justified in giving it by the course of events, 16 June 1794. He defended the London militia bill, 20 June 1794, 30 Mar. 1795, being himself an active officer. On 27 Aug. 1794 he assured the Duke of Portland, leader of the Whigs who had gone over to administration,
that in no moment of my life have I at all departed from that high esteem and veneration for your Grace’s character which was implanted in my mind from an early period. My political conduct has been entirely governed by a conviction of the unavoidable necessity of the war, from the conduct of our enemies abroad, and of strong measures at home from the conduct of our worse enemies in this country. The propriety of these opinions appears to me to be confirmed by the measures since pursued by many of those with whom I have always had the honour to act.
On 20 Jan. 1795 he opposed clamour for peace in common council
Newnham attended the London meetings to defend the bills against treason and sedition, 18, 20 Nov. 1795,
He died 26 Dec. 1809. An obituary singled out ‘his sweetness of disposition, his generosity, his benevolence and the warmth and steadiness of his attachments’. His elder brother Thomas (1735-1817) succeeded to his banking partnership, but relinquished it in 1812. Newnham’s will made no mention of his daughters, his wife Anne being sole beneficiary.
