rollope famously described the skuldugerry associated with the Railway Mania and all its swindles in The Way We Live Now, and readers have often remarked both that they saw similarities between Merdle in Charles Dickens's Little Dorrit and George Hudson, who occasioned Hudson’s Statue, Thomas Carlyle’s diatribe against democratic selection of leaders. Trollope’s great novel, which describes so much of the fraud and swindles of the past decades in our time, was not the first time he made this subject central to one of his novels. He had done so in his sixth novel, The Three Clerks, in a passage that not only generalizes about the way men who begin with high ideals succumb to temptation to act so badly but also rather surprisingly cites as an example Sir Robert Peel — “a politician without policy, as a statesman without a principle, as a worshipper at the altar of expediency, to whom neither vows sworn to friends, nor declarations made to his country, were in any way binding.”
In the course of his long attack on Peel he provides sufficient information to show us the most likely model for Augustus Melmotte in The Way We Live Now — neither the real-life George Hudson nor the fictional Merdle but the infamous John Sadleir (1813-1856). Near the beginning of the paragraphs about Peel, Trollope’s narrator admits, “It would shock many were we to attribute to him the roguery of the Sadleirs and Camerons, of the Robsons and Redpaths of the present day; but . . . Thrice in his political life did Sir Robert Peel change his political creed, and carry, or assist to carry, with more or less of self-gratulation, the measures of his adversaries.” All four men Trollope compared to Peel had recently committed fraud, embezzlement, and stock swindles, but the one who most closely matches Melmotte was Sadleir. As George Robb explains in White-Collar Crime in Modern England (2002),
The nation was shocked . . .by the exposure of John Sadleir's frauds at the Tipperary Joint-Stock Bank. As director of the bank, Sadleir had embezzled some £200,000. Another £400,000 was lost when the bank suspended payment. Sadleir had come to London in 1846 as an agent for Irish railway schemes. Augmenting his directorship of the Tipperary Bank, Sadleir became chairman of the London and County Bank and the Royal Swedish Railway. Elected to Parliament he was a spokesman for business interests and was eventually appointed a Lord of the Treasury. As it later transpired, Sadleir had buit his vaunted financial reputation on a series of monstrous impostures. Besides his embezzlements from the Tipperary Bank, he issued fictitious shares in the Swedish Railway to the extend of £150,000. While a member of the Irish Encumbered Estates Commission Sadleir also forged title deeds to a number of properties. Rumours of his misfeasance had forced his resignation from the Treasury and the London and County Bank, and the crash of the Tipperary Bank in January of 1856 laid bare his crimes. Sadleir immediately committed suicide, insiring Dickens to create the character of Mr. Merdle.
On the very heels of Sadleir's demise, the Royal British Bank failed amid revelations that the bank manager, Hugh Cameron, and two directors, Humphrey Brown and Edward Esdaile, had wasted the bank’s resources in unsecured loans to themselves and their friends. 
Note the parallels (1) a non-Englishman arrives in London, (2) sells fraudulent shares in a non-British railroad (forges shares for a real railway rather than selling real shares for a make-believe railway), (3) becomes elected to Parliament, (4) embezzles money in his care, (5) commits suicide. [After writing this I noted that the Wikipedia article on Sadleir cites the ODNB on the connection to Trollope, but does not mention The Three Clerks.]
Trollope, Anthony. The Three Cerks. Project Gutenberg E-text prepared by Andrew Turek and revised by Joseph E. Loewenstein, M.D., and an anonymous Project Gutenberg volunteer.
Robb, George. White-Collar Crime in Modern England: Financial Fraud and Financial Fraud and Business Morality, 1845-1929. Cambridge: Cambridge University Press, 2002.
Last modified 14 April 2016