[8] His elder brother Archibald Maclaine (1722–1804) was educated in Glasgow and followed his own vocation as presbyterian minister, scholar and royal preceptor in the Netherlands between 1746 and 1796, famous as the first translator (1765)[9] of Johann Lorenz von Mosheim's Ecclesiastical History (of 1726).

He attached himself to the domestic service of a Mr Howard in order to travel to England, and stayed with him for a while, but got into low company and, leaving without testimonials, returned to Ireland.

His mother's kin still refusing to help, his brother sent him subsidies and letters of good advice from The Hague: these proving insufficient, he considered joining the Irish Brigade in the French army, but was told that he would make little progress with them unless he became a Roman Catholic, which he was unwilling to do.

[12] His friends in London raised a small subscription to enable him to ship for Jamaica, but he took the money to the Masquerades (i.e. the public gardens) and squandered it at the gaming tables.

His business failing, owing (by his own account) to "an unavoidable trust reposed in servants", he sold off his stock and with whatever remained he turned his mind again to a military career.

[14] However, in passing himself off as a young gentleman in search of another wealthy wife, he had neither the funds nor the habitude necessary to rise above the accompanying inducements to profligacy.

He claimed that Plunkett, a fellow-Irishman, had led him to believe he had travelled abroad, and persuaded Maclaine to employ him in his household and to lend him £100, part of which was paid back sporadically.

[11] They committed around 20 highway robberies in six months, often in the then-relatively untamed Hyde Park: their victims included Sir Thomas Robinson of Vienna, and Mrs Talbot.

To allay suspicion he stayed awhile with his brother in Holland, giving him a false account of his means of living, and was introduced to polite dancing assemblies, where various purses and watches went missing.

[19] Walpole wrote,"One night, in the beginning of November 1749, as I was returning from Holland House by moonlight, about ten o'clock, I was attacked by two highwaymen in Hyde Park, and the pistol of one of them going off accidentally, raised the skin under my eye, left some marks of shot in my face, and stunned me.

offering him first refusal to buy back his stolen possessions, indicating that he should send a servant with the money to a rendezvous at Tyburn, and threatening fatal consequences to Walpole if he betrayed them.

Plunkett went forward of the carriage and took hold of the postilion, so that Lord Eglinton, who was carrying his famous blunderbuss, could not fire at him without killing his own servant.

[25] Between one and two o'clock in the morning of the same day, they held up the flying coach at Chiswick, between Turnham Green and Brentford, which was carrying six passengers on its way to Salisbury going westward out of London.

[11] A well-known print (an "Exact Representation"), showing Maclaine and "his accomplice" holding up Lord Eglinton's carriage, was published on 13 August 1750, about a month before his trial.

[11][33] At Maclaine's trial at the Old Bailey, on 12 September 1750,[26] he changed his plea again to Not Guilty, claiming that his former confession under examination had been the product of shock and mental derangement arising from the suddenness and unexpectedness of his arrest.

He claimed that he had Mr Higden's coat and other belongings because Plunkett had given them to him in lieu of the remaining money that he owed him, and he (Maclaine) had no idea that they were stolen.

"[29] Lord Eglinton declined to testify against him, and Walpole, reporting Maclaine's condemnation in a letter dated 20 September, added, "I am honourably mentioned in a Grub Street ballad for not having contributed to his sentence.

"[34] His romantic circumstances touched many hearts: a print entitled "Newgates Lamentation, or the Ladys Last Farewell of Macleane" illustrates visitors to his cell.

[35] He reputedly received nearly 3,000 guests while imprisoned at the Newgate, including a visitation en masse from White's, and his room became so hot that he fainted more than once.

Archibald expressed deep conflict between his compassion for the sinful man, his duty to uphold the path of righteousness, and his uncertainty of the true nature of his brother's repentance.

[39] The letter written by Archibald Maclaine to his "Unhappy Brother" on 22 September 1750 was a call to absolute repentance before God in knowledge of the coming Judgement.

When the judge asked him why he should not be sentenced, Maclaine, who had prepared a short speech expressing his contrition and pleading for mercy, was unable to say more than one or two words, "My lord, I cannot speak," and stood in silence.

The poet Thomas Gray, in his poem "A Long Story", referred to this when he wrote,"A sudden fit of ague shook him,He stood as mute as poor McLean.

A great crowd attended the execution, before whom he maintained a steady composure, and his last words to them were, "O God, forgive my enemies, bless my friends and receive my soul!

[24] After Maclaine was hanged, he earned a mention in the poem The Modern Fine Lady by Soame Jenyns: as an aside after the line "She weeps if but a handsome thief is hung" the following note was added: "Some of the brightest eyes were at this time in tears for one McLean, condemned for robbery on the highway."

A modern fictionalised portrayal of Maclaine's life appears in the 1999 film Plunkett & Macleane, in which he was played by Jonny Lee Miller.