The Counsellor soon discovered the place of his son's retreat, and, assisted by a liberal donation of gold, soon procured from the French ambassador at Madrid a warrant for the arrest of the fugitive, based upon the powers afforded by that infamous instrument of tyranny, the lettre de cachet. Once more the unhappy son had to fly; the Comte de Marcillac supplied him with money; and, embarking at the nearest port, he sailed for London, where he arrived in 1749. There, under the name of Monsieur de St. Etienne, he took a humble lodging in Paddington, then a country village with green fields all round it, from Marybone Farm to Kensington. His landlord was a market gardener.
His friends in France and Spain sent him remittances and letters of introduction to several persons of rank in London. To these, the pleasant manners, gentle bearing, and handsome person of the young Marquis speedily recommended him, and ere long he was enabled to remove nearer town, where he boarded with a Mrs. Giles, in Marybone—or, as another account has it, "with one Mrs. Bacon, a widow gentlewoman of much good nature and understanding." But even in this "land of liberty" he was not safe from the rancour of the indefatigable Counsellor, with his lettre de cachet.
The English friends of the Marquis having urged that he should lay the story of his wrongs before Louis the Fifteenth in the form of a memorial, the preparation of it was confided to an amanuensis, a Frenchman named Dages de Souchard. This fellow (though only the son of an obscure lawyer at Libourne, then a very small town of Provence) assumed, in London, the title of Baron. A deep-witted, crafty, and insinuating rascal, he contrived to propitiate many unsuspecting persons, and claimed to be a strict French Protestant, though he had, in early life, been a Franciscan monk, or friar minor, in a monastery at Nerac, in the west of France, and came of a family of rigid Catholics. Nay, while in the monastery, he seduced a young girl named Du Taux, whose mother was the lavandière of the establishment, and they had come together to London, where they gave themselves out as persecuted French Protestants. Having been born within twenty miles of Bordeaux, this Souchard knew the story of the Marquis de Fratteaux, and conceived the idea of turning it to his own profit before it should reach the ears of Louis the Fifteenth. For this purpose, delaying the preparation of the memorial, he wrote secretly to the Counsellor, stating that he knew where his son was, and offering to make terms to secure and deliver him up! The Counsellor entered cordially into the scheme, and, after remitting him some money on account, agreed to settle upon him for life a pension of six hundred livres, and to pay him two thousand English guineas down, with two hundred more, for the reward of any assistants or accomplices he might deem necessary.
Dages de Souchard immediately set about his treachery, and employed a man of most unscrupulous character, one Alexander Blasdale, a Marshal's Court officer who resided in St. Martin's Lane, and whose follower or colleague, by a strange coincidence, was the very Italian who had been accessory to the incarceration of the Marquis in the monastery near Bordeaux.
On the night of the 25th of March, 1752, they repaired to the lodgings of the Marquis: who immediately became deadly pale on seeing the Italian, and exclaimed, in alarm and distress:
"I am a dead man!"
Blasdale summoned him to surrender in the king's name. Knowing that he owed no man anything, Fratteaux was disposed to resist. His landlady sent for M. Robart, French clergyman, to whom Blasdale, with cool effrontery, showed a writ to arrest the Marquis for a pretended debt. The latter was persuaded to yield and to accompany the officer to his house in St. Martin's Lane, whither he was immediately driven in a hackney-coach, and there placed in a secure chamber.
Five gentlemen, "one of them a person of the first fashion," on hearing of the arrest, repaired to the bailiff, and in strong language warned him to beware of using the least violence towards his prisoner, lest he should be called to a severe account; and they added, that sufficient bail would be found for him in the morning. One gentleman, named M. Dubois, remained with the Marquis as his friend, resolved to see the end of the affair, and to protect him; but about midnight the Italian came in, saying that some one wished to speak with this gentleman below. On descending to the street, Dubois found only the bailiff Blasdale, who roughly told him "to be gone," and thrusting him out of the house, shut him out, and secured the door. On this gentleman returning with the French clergyman and others next morning, they were told by a servant-girl "that the Marquis was gone, in company with several gentlemen." They then demanded to see her master, but were curtly told that "he was out of town." In short, neither he nor his victim was ever beheld in England again!
Fears of foul play being immediately excited, the whole party repaired to Justice Fielding, by whom a warrant to apprehend Blasdale was issued, on suspicion of murder. Application was made to the Lord Chief Justice, and also to the secretary of state, Robert Earl of Holderness, for a habeas corpus to prevent the Marquis from being taken out of the kingdom dead or alive; but all was of no avail, and the fate of Fratteaux remained for some time a dark mystery.
It would appear that on finding himself alone, after the rough expulsion of his friend Dubois, the Marquis became furious with rage; on which Blasdale swore that as he made so much noise in the house he would convey him at once to jail. Fratteaux, who feared he might be assassinated where he was, readily consented to go to jail, and a hackney-coach was called. In it, he, the bailiff, and the nameless Italian, drove through various obscure streets and by-lanes. It was now about five in the morning.