About that time (1767), the personal liberty of the Englishman, though cherished as a theory, was subject to grievous infringements, and was almost daily violated. The impressment of men for the sea service was constantly practised, and, besides the press-gangs, there were regular bands of kidnappers employed in London and all the large towns of the kingdom, to seize men for the East India Company's service. And when the men were not wanted for India, they were shipped off to the planters in the American colonies. Negro slaves were openly advertised for sale in the London and Liverpool newspapers. Rewards were offered for recovering and securing fugitive slaves, and conveying them down to certain specified ships in the river.
The position of the reputed slave in England was undefined and doubtful. The judgments which had been given in the courts of law were fluctuating and various, resting on no settled principle.
Although it was a popular belief that no slave could breathe in England, there were legal men of eminence who expressed a directly contrary opinion. The lawyers to whom Mr. Sharp resorted for advice, in defending himself in the action raised against him in the case of Jonathan Strong, generally concurred in this view, and he was further told by Jonathan Strong's owner, that the eminent Lord Chief Justice Mansfield, and all the leading counsel, were decidedly of opinion that the slave, by coming into England, did not become free, but might legally be compelled to return again to the plantations. Such information would have caused despair in a mind less courageous and earnest than that of Granville Sharp; but it only served to stimulate his resolution to fight the battle of the negroes' freedom, at least in England. "Forsaken," he said, "by my professional defenders, I was compelled, through the want of regular legal assistance, to make a hopeless attempt at self-defence, though I was totally unacquainted either with the practice of the law or the foundations of it, having never opened a law book (except the Bible) in my life, until that time, when I most reluctantly undertook to search the indexes of a law library, which my bookseller had lately purchased."The whole of his time during the day was occupied with the business of the ordnance department, where he held the most laborious post in the office; he was therefore under the necessity of conducting his new studies late at night or early in the morning. He confessed that he was himself becoming a sort of slave. Writing to a clerical friend to excuse himself for delay in replying to a letter, he said, "I profess myself entirely incapable of holding a literary correspondence. What little time I have been able to save from sleep at night, and early in the morning, has been necessarily employed in the examination of some points of law, which admitted of no delay, and yet required the most diligent researches and examination in my study."Mr. Sharp gave up every leisure moment that he could command during the next two years, to the close study of the laws of England affecting personal liberty, - wading through an immense mass of dry and repulsive literature, and making extracts of all the most important Acts of Parliament, decisions of the courts, and opinions of eminent lawyers, as he went along. In this tedious and protracted inquiry he had no instructor, nor assistant, nor adviser. He could not find a single lawyer whose opinion was favourable to his undertaking. The results of his inquiries were, however, as gratifying to himself, as they were surprising to the gentlemen of the law. "God be thanked," he wrote, "there is nothing in any English law or statute - at least that I am able to find out - that can justify the enslaving of others." He had planted his foot firm, and now he doubted nothing. He drew up the result of his studies in a summary form; it was a plain, clear, and manly statement, entitled, 'On the Injustice of Tolerating Slavery in England;' and numerous copies, made by himself, were circulated by him amongst the most eminent lawyers of the time. Strong's owner, finding the sort of man he had to deal with, invented various pretexts for deferring the suit against Sharp, and at length offered a compromise, which was rejected. Granville went on circulating his manuscript tract among the lawyers, until at length those employed against Jonathan Strong were deterred from proceeding further, and the result was, that the plaintiff was compelled to pay treble costs for not bringing forward his action.
The tract was then printed in 1769.
In the mean time other cases occurred of the kidnapping of negroes in London, and their shipment to the West Indies for sale.
Wherever Sharp could lay hold of any such case, he at once took proceedings to rescue the negro. Thus the wife of one Hylas, an African, was seized, and despatched to Barbadoes; on which Sharp, in the name of Hylas, instituted legal proceedings against the aggressor, obtained a verdict with damages, and Hylas's wife was brought back to England free.