The phrase dirty work at the crossroads denotes dishonest or illicit dealings.
Since the late 18th century, the noun crossroads has been used figuratively to denote the point at which an important choice has to be made; but the phrase dirty work at the crossroads probably alludes to crossroads as settings for sinister actions. In particular, the crossroads were formerly used as burial places for suicides; among the mentions of this custom that I have found is the following from the Ipswich Journal (Ipswich, Suffolk) of Saturday 23rd August 1800:
Charles Smith, alias Jeremiah Clay, having hanged himself in Giltspur-street Compter, where he was taken on a charge of having forged a check on the house of Prescott and Co. for 30l. 4s. was on Tuesday ordered by the Coroner’s Jury to be buried in the cross-roads at the head of the Old Bailey, and a stake drove through his body.
The Globe (London) of Monday 3rd August 1818 reported a coroner named Hugh Lewis as declaring that the custom of burying suicides in the crossroads served “as a preventive to the crime”. However, The British Magazine, and Monthly Register of Religious and Ecclesiastical Information, Parochial History, and Documents Respecting the State of the Poor, Progress of Education, &c. (London) of October 1835 published an article titled Gresford Church, which explains that it was usual
to erect crosses at the junction of four cross-roads, as a place self-consecrated, according to the piety of the age; and it was not, as now, with a notion of indignity, but in a spirit of charity, that those excluded from more holy rites were buried at the crossing roads, as places next in sanctity to consecrated ground.
Likewise, the column Do you know?, in the Nottingham Evening Post (Nottingham, Nottinghamshire) of Saturday 10th October 1925, gave the following explanation:
Suicides used to be buried at cross-roads because the fact of the cross being there made them the nearest approach to consecrated ground.
This notion appears in the following tale, from the column Notes and Queries, in the Cheltenham Chronicle and Gloucestershire Graphic (Cheltenham, Gloucestershire) of Saturday 4th September 1909:
There is a story in Russia of a girl who danced on the village green with an unknown and handsome young man who solicited the honour of her hand. Anxious to make sure of his good character, she one day followed him until he vanished into a church. Peeping through the window she beheld him devouring a corpse which was awaiting burial. He was an incarnate demon—there are plenty of them about. Knowing that she had learned his secret and would never enjoy dancing with him any more, he cursed her to death. Before dying she took the precaution of telling the priest to bury her at a cross-roads. He did so and a flower sprung up over her grave. A prince came by and dug up the flower and kept it in his house. It turned into a maiden again, because she had been buried at a crossroads and therefore at the Cross by which death ends in Resurrection. The demon-lover immediately came after her. She sprinkled him with holy water, and he turned into a handful of ashes. She lived happy as the princess for ever after.
The earliest occurrence of dirty work at the crossroads that I have found is from the following poem, published in The Citizen (Gloucester, Gloucestershire) of Wednesday 30th May 1906. Here, the phrase refers to Barber’s Bridge monument, in Gloucestershire, standing as a memorial to the Welsh Royalists who were attacked there by Parliamentarians in 1643, during the English Civil War; the monument stands on the burial pit of the Royalists, which was discovered in the 19th century during the construction of a railway; an inscription reads: “These stones taken from the ancient walls of the city of Gloucester mark the burial place of the Welsh of Lord Herbert’s force who fell in the combined attack of Sir William Waller and Colonel Massey, on their entrenchments at Highnam. March 24. 1643.”:
There be hares at Rudford, buttercups and crops,
Cows and calves in clover, but no trams or shops;
There be pleasant pastures, and many a leafy lane;
So take me back to Rudford, so take be [sic] back again.
Take me back to Rudford,
By the ten-to-seven train.
There be teams at Tibberton, for cricket and for plough;
While apple blossoms seem to sing of cider on the bough;
There be pleasant welcomes, in sunshine or in rain;
So take me back to Tibberton, so take me back again.
Take me back to Tibberton,
By the ten-to-seven train.
There be writ at Barber’s Bridge a tale of long ago,
Of dirty work at those cross-roads, of blood that there did flow;
But now the lark sings overhead, and peace is o’er the plain;
So take me back to Barber’s Bridge, so take me back again.
Take me back to Barber’s Bridge,
By the ten-to-seven train.
The second-earliest instance that I have found is from the column Cockney Cackle, in The Scottish Referee: A Record and Review of Outdoor Recreation (Glasgow, Scotland) of Monday 7th October 1907—it is unfortunately impossible to know what the phrase exactly refers to in this case; the diabolo (formerly devil on two sticks) is a two-headed top which is thrown up and caught with a string stretched between two sticks:
Now again as to this diabolo business. [Tighten the strings, throw the devil to the winds, and get on with your stuff.—Editor.] “Stuff!”—egad! that’s a heavy ’un! However—no matter: there may be dirty work at the cross-roads to-night! ha! ha! You know, if one is in London just now, there is but little save —— (name deleted by order of the Editor), and if you don’t write about and speak about —— (name again deleted by order of the Editor), you cannot consider yourself “in the movement.”